Kootenai National Forest Avalanche Advisory – 4/4/2014

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

THIS ADVISORY HAS EXPIRED

Issued: April 4, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. This is the last scheduled advisory for the Kootenai National Forest area. 


MOUNTAIN WEATHER 

WeatherGraphic

Since the Tuesday morning (April 1st) advisory, only small amounts of snow (SWE 0.0- 0.2 inches) fell at Kootenai snotel sites (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Winds on Friday through Monday were light from the southwest.  All sites experienced melt-freeze cycles through Monday with night time low temperatures in the upper 20s F and day time highs in the low 40s F.  

FORECAST:  Cloudy skies Friday through Sunday.  All daytime temperatures are forecasted to be above freezing in the low 40s F with night time temperatures in the upper 20s F.  Winds will be from the west/southwest direction at 13 – 17 mph.  Chance of snow is 50-90% through Sunday with 8 – 12 inches forecasted.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Chicago Peak in the East Cabinets located 23 air miles south of Libby on April 3rd.  Total snow depth was about 100 inches on west aspects at 6,000 feet elevation.   A three inch knife hard crust sits on top of a five inch one finger hard slab.  Below these surface layers is a four inch pencil hard slab that releases cleanly (Quality 1 shear) with moderate force in stability tests.  Below these top layers are very hard crusts and hard slab several feet thick.  The upper 20 inches of the snowpack releases roughly (Quality 3 shears) with moderate force in compression (stability) tests.  Currently, there are no significant temperature gradients in the snowpack.


 

SNOWPACK DISCUSSION

Avalanche Problem #1

Wind Slab

Southwest wind events transport snow onto east and northeast aspects. Wind slabs can take up to a week to gain strength, and steep wind loaded slopes should still be treated as suspect. It remains important to assess the stability of each slope you intend to ski or ride. From a distance these will be quite obvious due their smooth, raised, and rounded appearance.  Most of these slabs are hard and may have a hollow sound.  Wind slabs should be identified and avoided.

 

 

 


Avalanche Problem #2 

CorniceCornice fall is the release of an overhanging mass of snow that forms when the wind moves snow over a sharp terrain features such as ridge.  Cornices range in size from small wind lips to huge overhangs of hard snow.  They can break off the terrain suddenly and trigger slab avalanches.  Cornice locations are easily identified and should be avoided.

 

 


TREND: Moderate to heavy storm loading (8-12 inches) is forecasted Friday morning through Sunday.  I expect wind transport (southwest/west 13 – 17 mph) of this new snow.  Temperatures are forecasted to be above freezing during the day in the low 40s, and night time in the upper 20s through Sunday.  The trend is for avalanche hazard to increase through this period due to new snow and wind.


 

  BOTTOM LINE

For today, the avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is MODERATE.  This means that heightened avalanche conditions exist on specific terrain features.  Natural avalanches are unlikely, and human triggered avalanches are possible.  Evaluate snowpack and terrain carefully, identify features of concern.

Snowpack conditions have improved with melt-freeze cycles in the absence of storm loading, wind transport, or rain on snow events.  Forecast is for storm loading and wind transport through Sunday.  The trend is for avalanche hazard to increase through this period due to new snow and wind.


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 4/1/2014

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

THIS ADVISORY HAS EXPIRED

Issued: April 1, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The last scheduled advisory for the Kootenai National Forest area will be Friday, April 4, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Friday morning (March 28th) advisory, heavy snow (SWE 1.3- 1.9 inches) accumulated at Kootenai SNOTEL sites (Bear Mtn, Hawkins Lake, Poorman Cr). Banfield Mountain in the southeast Purcell Range was the exception with 0.4 inches SWE.  Winds Friday through Monday were light from the southwest.  All sites have experienced melt-freeze cycles through Monday.  Night time low temps in the upper 20s F and day time highs in the upper 30s F.  

FORECAST:  Partly cloudy skies Tuesday through Thursday.  All daytime temperatures are forecasted to be above freezing in the low 40s F, with night time temperatures in the upper 20s F.  Winds will be variable in direction at 3 – 6 mph Tuesday through Thursday.  Chance of snow is 0-30% through Thursday with trace accumulations forecasted.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Twin Peaks in the West Cabinets located 30 air miles west of Libby on March 31st.  Total snow depth was about 105 inches on a west aspect at 6,000 feet.   One inch of new snow sits atop a sun crust.  Below these surface layers is a soft three inch deep graupel deposit overlaying a nine inch hard slab.  All of the above layers formed in the last four days.  Below these top layers, is a very complicated mix of knife hard crusts and hard slab material about 16 inches thick.  The upper 10 inches of the snowpack releases cleanly (Quality 1 shears) easy force in stability tests.  The mid pack hard slabs release cleanly with hard force.  The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are NO significant temperature gradients in the snowpack to drive change processes.

 

Graupel of 2-4mm from a 3 inch thick deposit this weekend. 3/31/2014.

Graupel of 2-4mm from a 3 inch thick deposit this weekend. 3/31/2014.

 

Bear Mountain Snotel 5400’ with Rattle Mountain 6079’ in background. 3/31/2014.

Bear Mountain Snotel 5400’ with Rattle Mountain 6079’ in background. 3/31/2014.

 

 

 

 

 

 

 

 

 

 


 

   SNOWPACK DISCUSSION

Avalanche Problem #1

Wind Slab

Southwest wind events have transported snow onto east and northeast aspects.  From a distance these are quite obvious to the observer due their smooth, raised, rounded appearance.  Most of these slabs are hard and may have a hollow sound when traveled upon.  Wind slabs should be identified and avoided. 

 

 

 


Avalanche Problem #2 

CorniceCornice fall is the release of an overhanging mass of snow that forms when the wind moves snow over a sharp terrain features such as ridge.  Cornices range in size from small wind lips to huge overhangs of hard snow.  They can break off the terrain suddenly and trigger slab avalanches.  Cornice locations should be identified and avoided.

 

 


TREND: Light storm loading is expected Tuesday morning through Thursday with a trace of snow accumulations. Temperatures are forecasted to be above freezing daytime in the low 40s F, and night time in the upper 20s F through Thursday.  


 

  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is MODERATE.  This means that heightened avalanche conditions exist on specific terrain features, such as wind loaded slopes.  Natural avalanches are unlikely, and human triggered avalanches are possible.  Evaluate snowpack and terrain carefully and identify features of concern.


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/28/2014

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

THIS ADVISORY HAS EXPIRED

Issued: March 28, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Tuesday, April 1, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Tuesday morning (March 25th) advisory moderate amounts of snow (SWE 0.2- 0.9 inches) have fallen at all Kootenai snotel sites (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Winds Wednesday through Thursday were strong from the southwest but with minor snow transport.  Temperatures at all sites have been above freezing during the day with brief freezing at night through Thursday.  There is a little soft new snow available for wind transport at all sites in our Ranges.

FORECAST:  Mostly cloudy skies Friday through Sunday.  All daytime temperatures are forecasted to be above freezing in the mid/upper 30s F, with night time temperatures in the upper 20s F.  Winds will be out of the southwest at 8 – 12 mph.  Chance of snow is 60-100% through Sunday with accumulations of 7- 12 inches forecasted.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Allen Peak in the East Cabinets located 31 air miles south of Libby on March 27th.  85 to 90 inches of snow was encountered on east aspects at 6,000 feet elevation.   Two inches of new snow sits atop a 1 inch sun crust.  Below these surface layers is a very complicated mix of knife hard crusts and hard slab material to a thickness of 12 inches.  There is no free water present in any layers of the snow column. The upper 14 inches of the snowpack releases cleanly (Quality 1 shears) with 3 – 5 wrist taps using the compression test.  The mid pack hard slabs release cleanly with hard force.  The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are no significant temperature gradients in the snowpack to drive change processes.

I also received a report of a hard slab wind deposit that released naturally to produce a D2/R3 slide in the West Cabinets near Twin Peaks.  This is just south of the popular Keeler snowmobiling area southwest of Troy.

   

 


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

Wind Slab

Recent southwest wind events have transported snow onto east and northeast aspects.  From a distance these are quite obvious to the observer due their smooth, raised, rounded appearance.  Most of these slabs are hard and may have a hollow sound when traveled upon (NOT RECOMMENDED!).  Wind slabs should be identified and avoided. 

 

 


Avalanche Problem #2

WetAvalRain on snow can also increase the chances of wet avalnaches. Be aware of changing weather conditions, specifically rain on snow or rapidly rising temperatures. If travelling on or below sun exposed slopes consider turning around or moving to shaded areas if the snow surface becomes wet, skis or boots sink deep into the snow, or pin wheels or roller balls start to form on steep slopes.  

 

 


 

Avalanche Problem #3 

CorniceCornice fall is the release of an overhanging mass of snow that forms when the wind moves snow over a sharp terrain features such as ridge.  Cornices range in size from small wind lips to huge overhangs of hard snow.  They can break off the terrain suddenly and trigger slab avalanches.  Cornice locations should be identified and avoided.

 

 


 

TREND: Heavy storm loading is forecasted Friday morning through Sunday with 0.5 inches of rain and 7–12 inches of  snow expected.  We expect some wind transport (southwest winds of 8 – 12 mph) of new snow.  Temperatures are forecasted to be above freezing daytime in the mid/upper 30s F, and night time in the upper 20s F through Sunday.  The trend is for avalnache hazard to increase through this period.


 

  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is MODERATE.  This means that heightened avalanche conditions exist on specific terrain features, such as wind deposits.  Natural avalanches are unlikely, and human triggered avalanches are possible.  Evaluate snowpack and terrain carefully, identify features of concern.

SPECIAL NOTE:  Snowpack conditions have improved with melt-freeze cycles in the absence of storm loading, wind transport, or rain on snow events.  Next round of weather will include storm loading, possible rain on snow, and a little wind transport. The avalanche hazard is expected to increase through Sunday.


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/25/2014

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

THIS ADVISORY HAS EXPIRED

Issued: March 25, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Friday, March 28, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Friday morning (March 21st) advisory,  amounts of snow (SWE 0.2- 0.6 inches) have fallen at all Kootenai snotel sites (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Winds Friday through Monday were light from the southwest. Temperatures at all sites have been below freezing day and night through Saturday. Thereafter, we have had above freezing temps Sunday and Monday afternoon. 

FORECAST:  Mostly cloudy skies Tuesday through Thursday.  All daytime temperatures are forecasted to be above freezing in the mid/upper 30s, with night time temperatures in the upper 20s.  Winds will be out of the southwest at 5 – 12 mph Tuesday through Thursday.  Chance of snow is 30-80% through Sunday with accumulations of 10- 12 inches forecasted.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Flatiron Mountain in the Purcell Range located 21 air miles north of Libby on March 24th.  70 to 75 inches of total snow depth was encountered on east aspects at 5,891 ft. elevation.   A 1 inch thick suncrust sits atop 4 inches of new snow.  Melt-freeze cycles have stiffened the upper layers of the snowpack.  There is no free water present in any layers of the snow column. The upper 20 inches of the snowpack releases with 8 – 12 inch drop heights using the stuff block test.  The mid pack hard slabs release cleanly with hard force.  The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are no significant temperature gradients in the snowpack.

   

 


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

Wind Slab

Recent southwest wind events havetransported snow onto east and northeast aspects.  From a distance these are quite obvious to the observer due their smooth, raised, rounded appearance.  Most of these slabs are hard and may have a hollow sound when traveled upon (NOT RECOMMENDED!).  Wind slabs should be identified and avoided. 

 

 


Avalanche Problem #2

WetAvalTemperatures are expected to be warmer tomorrow increasing the wet avalanche hazard, particularly on sun exposed slopes. Be aware of changing weather conditions, specifically rapidly rising temperatures. If travelling on or below sun exposed slopes consider turning around or moving to shaded areas if the snow surface becomes wet, skis or boots sink deep into the snow, or pin wheels or roller balls start to form on steep slopes.  

 

 


 

Avalanche Problem #3 

CorniceCornice fall is the release of an overhanging mass of snow that forms when the wind moves snow over a sharp terrain features such as ridge.  Cornices range in size from small wind lips to huge overhangs of hard snow.  They can break off the terrain suddenly and trigger slab avalanches.  Cornice locations should be identified and avoided.

 

 



TREND: Heavy storm loading is the forecasted Tuesday monrning through Thursday with 0.5 inches of rain and 10-12 inches of new snow accumulations.  We expect light to moderate winds (5-15 mph) out of the southwest.  Temperatures are forecasted to be above freezing daytime in the mid/upper 30s, and night time in the upper 20s through Thursday.  The trend is for hazard to increase through this period. 


  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is MODERATE but could increase with new snow and rain.  This means that heightened avalanche conditions exist on specific terrain features, such as wind deposits.  Natural avalanches are unlikely, and human triggered avalanches are possible.  Evaluate snowpack and terrain carefully, identify features of concern.

SPECIAL NOTE:  Snowpack conditions have improved with melt-freeze cycles in the absence of storm loading, wind transport, or rain on snow events.  Next round of weather will include storm loading, possible rain on snow, and some wind transport. 


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/21/2014

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

THIS ADVISORY HAS EXPIRED

Issued: March 21, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Tuesday, March 25, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Tuesday morning (March 18th) advisory, moderate amounts of snow (SWE 0.3 – 1.0 inches) have fallen at all Kootenai snotel sites (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Winds Tuesday through Thursday were from the southwest at variable speeds with moderate snow transport.  Temperatures at all sites have been below freezing day and night.  There is soft new snow available for wind transport at all sites in our ranges.

FORECAST:  Partly cloudy skies Friday through Sunday.  All daytime temperatures are forecasted to be near freezing in the low 30s F with night time temperatures in the low 20s F.  Winds will be extremely variable by direction at 3 – 5 mph.  Chance of snow is 20-50% through Sunday with accumulations of 2- 4 inches forecasted.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Cheer Ridge in the West Cabinets located 29 air miles west of Libby on March 20th.  Total snow depth was 125 to 130 inches on southeast aspects at 6,000’ elevation.  Four inches of new snow sits atop a 4 inch soft slab .  There is no free water present in any layers of the snow column. The upper 16 inches of the snowpack releases easily with a 4 inch drop height using the stuff block stress test.  The failing layer is 2 mm irregular columns.  The mid pack hard slabs release cleanly with hard force. The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are no significant temperature gradients in the snowpack to drive change processes.

View of Bear Mountain 6,061’ east side from Cheer Ridge. 3/20/2014.

View of Bear Mountain 6,061’ east side from Cheer Ridge. 3/20/2014.


Snowmobile play areas below Drift Peak. 3/20/3014,

Snowmobile play areas below Drift Peak. 3/20/3014,


Wind deposits near view and far from Cheer Ridge. 3/20/2014.

Wind deposits near view and far from Cheer Ridge. 3/20/2014.

 

 

 

 

 

 

 

 

 

   


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

Wind Slab

Recent southwest wind events have “pillowed” snow onto east and northeast aspects.  From a distance these are quite obvious to the observer due their smooth, raised, rounded appearance.  Most of these slabs are hard and may have a hollow sound when traveled upon (NOT RECOMMENDED!).  Wind slabs should be identified and avoided. 

 

 

 


 

 Avalanche Problem #2 

CorniceCornice fall is the release of an overhanging mass of snow that forms when the wind moves snow over a sharp terrain features such as ridge.  Cornices range in size from small wind lips to huge overhangs of hard snow.  They can break off the terrain suddenly and trigger slab avalanches.  Cornice locations should be identified and avoided.

 

 

 

 


TREND:  Light storm loading is the forecasted Friday morning through Sunday with 2–4 inches snow accumulations.  Temperatures are forecasted to be near freezing daytime in the low 30s, and night time in the low 20s through Sunday.  


  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is MODERATE.  This means that heightened avalanche conditions exist on specific terrain features, such as wind deposits.  Natural avalanches are unlikely, and human triggered avalanches are possible.  Evaluate snowpack and terrain carefully, identify features of concern.

SPECIAL NOTE:  Near surface layers (surface to 16 inches deep) release with ease but not cleanly.  Continued below freezing temperatures in the absence of storm loading, wind transport, and rain on snow will improve snowpack conditions. 


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/18/2014

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

THIS ADVISORY HAS EXPIRED

Issued: March 18, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Friday, March 21, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Friday morning (March 14th) advisory, heavy amounts of snow (snow water equivalent 1.1- 4.9 inches) accumulated at all SNOTEL sites in the Kooteani advisory area (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Winds Friday through Monday were from the southwest at variable speeds with a bit of snow transport of new snow.  Temperatures at all sites have been mostly above freezing except for a few brief freezing periods. There is soft new snow available for wind transport within our advisory area.

FORECAST:  Mostly cloudy skies Tuesday through Thursday.  All daytime temperatures are forecasted to be near freezing in the low 30s F, with night time temperatures in the mid 20s F.  Winds will be out of the southwest at 8 – 13 mph Tuesday through Thursday. Chance of snow is 20-80% through Thursday with accumulations of 8” – 13” forecasted.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Poorman Basin in the East Cabinets located 17 air miles south of Libby on March 17th.  Total snow depth is 95-100 inches on a southeast aspect at 5500 feet. Four inches of new snow sits atop a 10 inch rain saturated layer from Sunday night.  Below this rain layer is wet snow 12 inches thick from last Friday. The upper 14 inches of the snowpack releases easily using the compression stress test.  The mid pack hard slabs release cleanly with moderate to hard force.  Below these snow layers is the old snow melt-freeze crust.  The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are no significant temperature gradients in the snowpack to drive change processes. 

D2/R3 rain triggered debris from 03/17/2014.

D2/R3 rain triggered debris from 03/17/2014.


03/10/2014 debris damming Poorman Creek. Taken: 3/17/2014.

03/10/2014 debris damming Poorman Creek. Taken: 3/17/2014.


D4/R4 rain triggered wet slab from 03/06/2014 . Taken: 3/17/2014.

D4/R4 rain triggered wet slab from 03/06/2014 . Taken: 3/17/2014.


Snomobile parked near 03/10/2014 rain triggered wet slab debris. Taken: 3/17/2014.

Snomobile parked near 03/10/2014 rain triggered wet slab debris. Taken: 3/17/2014.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

 Wet SlabWe have experienced exceptional rain on snow loading through 03/17/2014.  Rain triggered slab releases were common 03/06/2014 and 03/10/2014, and again yesterday (3/17/).  However, the natural releases yesterday appear to be “clean up” releases that ran as smaller (D2/R3) events.  Back country travel during or immediately after significant rain on snow events is NOT recommended.

 

 

 


 

 Avalanche Problem #2 

Glide

With abundant rainfall on snow since 03/04/2014, steep snow packs over bedrock or smooth slopes have developed cracks and full depth glide cracks exist. These locations should be identified and avoided.

 

 

 

 


TREND:  New snow is forecasted Tuesday morning through Thursday with 8 – 13 inches expected.  We expect wind transport (SW 8 -13 mph) of new snow.  Temperatures are forecasted to be near freezing daytime in the low 30s, and night time in the mid 20s through Thursday.  


  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is CONSIDERABLE.  This means that dangerous avalanche conditions exist on many terrain features, especially during the height of day time heating.  Natural avalanches are possible, and human triggered avalanches are likely.  Careful snowpack evaluation, cautious route finding, and conservative decision making are essential.

SPECIAL NOTE:  Significant rain on snow is the most destructive agent to snowpack stability.  If it has rained just before or during your back country trip, have a safe exit route in your travel plans and use it!  Rain triggered wet slabs are hugely destructive and have low survivability potential.


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/14/2014

THIS ADVISORY HAS EXPIRED

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

Issued: March 14, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Tuesday, March 18, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Tuesday morning (March 11th) advisory, heavy amounts of snow (SWE 1.1”- 2.0”) have fallen in the East and West Cabinet Ranges at Kootenai snotel sites (Bear Mtn, Poorman Cr).  In the Purcell Range light amounts of snow (SWE 0.2”) have fallen.  Winds Tuesday through Thursday were from the southwest at variable speeds.  Temperatures at all sites have followed daily melt (upper 30s F) freeze (upper 20s F) cycles.  There is little soft snow available for wind transport at all sites in our Ranges due temperature impacts.

FORECAST:  Partly cloudy skies Friday through Sunday.  All daytime temperatures are forecasted to be above freezing in the upper 30s/low 40s, with night time temperatures in the mid to upper 20s.  Winds will be out of the southwest at 6 – 18 mph with LOW probability of snow transport Friday through Sunday due to temperature impacts to snow surfaces.  Chance of snow is 70-100% Friday with accumulations of 4” -6” forecasted


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to China Basin in the Purcells located 12 air miles northwest of Libby on March 13th.  90” to 95” of snow was encountered on east aspects at 6,000’ elevation.  4” of temperature modified new snow sits atop a 5” knife hard rain crust from the last rain on snow events.  Below this rain crust there only hard slab layers (1 finger/pencil hardness). The upper 10” of the snowpack releases easily and cleanly with 5 wrist taps using the compression stress test.  Several prolonged cold nights have help solidify the snowpack.  The mid pack hard slabs release cleanly with moderate to hard force.  Below these snow layers is the old snow melt-freeze crust.  The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are no significant temperature gradients in the snowpack to drive change processes. 

 

Debris field from other China Basin avalanche. Vertical fall 250’. 3/13/2014.

Debris field from other China Basin avalanche. Vertical fall 250’. 3/13/2014.


Wind deposit crown fracture (12’ at deepest) associated with avy incident from backside of China Basin. 3/13/2014.

Wind deposit crown fracture (12’ at deepest) associated with avy incident from backside of China Basin. 3/13/2014.


Wind deposit crown fracture (7’ at deepest) associated with another avalanche from front side of China Basin. 3/13/2014.

Wind deposit crown fracture (7’ at deepest) associated with another avalanche from front side of China Basin. 3/13/2014.


Debris field from China Basin wind slab. Vertical fall 700’. 3/13/2014.

Debris field from China Basin wind slab. Vertical fall 700’. 3/13/2014.

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

Persistent Slab We have cohesive layers of hard snow positioned in the upper part of our snowpack.  When the bond to an underlying persistent weak layer breaks, these hard slabs release.  Our weak layers are associated with buried surface hoar and near surface facets.  Persistent weak layers can produce avalanches over long periods of time, making them dangerous and tricky to forecast.

 


 

 Avalanche Problem #2 

Wind SlabWinds in the Kootenai region typically transport soft snow from west/southwest aspects to deposit it on east/northeast aspects.  Subtle terrain variations modify this pattern.  Wind slabs are often smooth and rounded, and may sound hollow when traveled on.  These locations should be identified and avoided.

 

 


 

Avalanche Problem #3

WetAval

There will be increased potential for loose wet avalanches within recent unconsolidated snow as well as the potential for wet slab avalanches. Also, keep in mind that recently formed cornices may become more sensitive with warmer temperatures, continue to give them a wide safety margin when traveling above them and avoid travel below. Pay attention to the clues that warming temperatures are making the snowpack unstable like snow surface becoming wet, skis or boots penetrate deeper into the snow, or pin wheels start to roll.

 

TREND:  No significant storm loading is the forecasted Friday morning through Sunday.  We expect light wind transport (SW 6 -18 mph) of snow from Friday’s storm (4 -6”).  Temperatures are forecasted to be above freezing daytime in the upper 30s, and night time in the upper 20s through Sunday.  


  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is CONSIDERABLE.  This means that dangerous avalanche conditions exist on many terrain features, especially during the height of day time heating.  Natural avalanches are possible, and human triggered avalanches are likely.  Careful snowpack evaluation, cautious route finding, and conservative decision making are essential.

SPECIAL NOTE:  Conditions change as day time heating progresses.  Be alert to this change especially on sun exposed slopes. 


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/11/2014

THIS ADVISORY HAS EXPIRED.

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

Issued: March 11, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Friday, March 14, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Friday morning (March 7th) advisory, heavy amounts of rain (1.6”- 5.4”) have fallen at Kootenai SNOTEL sites (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Tuesday through Thursday winds were from the southwest at variable speeds.  Temperatures at all sites have been above freezing for the last four days except early Saturday morning.  

FORECAST:  Partly cloudy skies Tuesday through Thursday.  All daytime temperatures are forecasted to be above freezing in the upper 30s F, with night time temperatures in the mid to upper 20s F.  Winds will be out of the southwest at 4 – 9 mph.  No new snow is expected Tuesday through Thursday.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Libby Creek Basin in the East Cabinets located 20 air miles south of Libby on March 10th.  80 to 85 inches of snow was encountered on southeast aspects at 5,300’ elevation.  The top 16 inches of the snowpack consists of heavy wet snow that was rained upon Tuesday morning through Friday as well as Sunday morning through Monday.  This wet surface snow releases with moderate force in stability tests.  The next 20 inch layer is colder snow without free water present.  This slab releases cleanly but with moderate force.  Below these snow layers is the old snow melt-freeze crust.  The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are no significant temperature gradients in the snowpack.

 

Rain triggered wet slab release from Monday AM.  Slide is just NW of the Montanore adit site. 3/10/2014.

Rain triggered wet slab release from Monday AM. Slide is just NW of the Montanore adit site. 3/10/2014.


This is a D3/R3 release that we saw so much of last Thursday.  Debris pile is 12-15 feet high of super dense material. 3/10/2014.

This is a D3/R3 release that we saw so much of last Thursday. Debris pile is 12-15 feet high of super dense material. 3/10/2014.


This is a D4/R4 wet slab from last Thursday.  D4s can destroy rail cars, big trucks. 3/10/2014.

This is a D4/R4 wet slab from last Thursday. D4s can destroy rail cars, big trucks. 3/10/2014.

 

 

 

 

 

 

 

 

 

 

 

 


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

 Wet SlabWe have experienced exceptional rain on snow loading through 03/10/2014.  Rain triggered slab releases on old snow surfaces were common last Thursday morning and again Monday morning.  You can reduce your risk from wet slabs by waiting for the rain to cease and cooler temperatures to arrive before venturing out into the backcountry.  ALL avalanche terrain (starting zones, tracks, and run outs) should be avoided.

 


 

 Avalanche Problem #2 

GlideWith abundant rainfall on snow since last Tuesday morning (03-04-2014), steep snowpacks over bedrock and smooth slopes have developed glide cracks.  Nearly every drainage within the East Cabinets exhibits several of these slides to the ground.  These locations should be identified and avoided.

 

 


TREND:  NO rain or storm loading is forecasted Tuesday morning through Thursday. Temperatures are forecasted to be above freezing during the day reaching the upper 30s F, and night time temperatures in the upper 20s F through Thursday.   


  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range is CONSIDERABLE.  This means that dangerous avalanche conditions exist on many terrain features, such as steep semi open slopes.  Natural avalanches are possible, and human triggered avalanches are likely.  Careful snowpack evaluation, cautious route finding, and conservative decision making are essential.

Tuesday morning several rain triggered natural slab releases were observed in the East Cabinets.  They started near ridgelines at approximately 6,000 feet and ran as large avalanches.  This means they could bury/destroy a car and involve approximately 80% of the historic avalanche path (see attached photos).  We believe this activity will gradually decrease when the rain stops and cooler night time temperatures arrive. 


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/7/2014

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

THIS ADVISORY HAS EXPIRED

Issued: March 7, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Tuesday, March 11, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Tuesday AM (March 4th) advisory, HEAVY amounts of rain/snow (SWE 1.2”- 4.2”) have fallen at Kootenai snotel sites (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Winds Tuesday through Thursday were from the southwest at variable speeds with NO snow transport due rain impacts to surface snow.  Temperatures at all sites have been above freezing for the last three days.  There is little soft snow available for wind transport at all sites in our Ranges due rain impacts.

FORECAST:  Mostly cloudy skies Friday through Sunday.  All daytime temperatures are forecasted to be above freezing in the upper 30s F, with night time temperatures in the upper 20s.  Winds will be out of the southwest at 8 – 16 mph with LOW probability of snow transport Friday through Sunday due to rain impacts to snow surfaces.  Chance of snow is 50% Friday AM with minimal accumulations.  Chance of rain 100% Saturday PM through Sunday PM, with 0.50” forecasted.  THIS COULD BE ANOTHER RAIN TRIGGERING EVENT CYCLE SIMILAR TO WHAT WE EXPERIENCED THURSDAY AM.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Bear Creek Basin in the East Cabinets located 16 air miles southwest of Libby on March 6th.  95 – 100 inches of snow was encountered on south aspects at 5,500 ft. elevation.  The top 14 inches of the snowpack consists of heavy new snow from Monday that was rained upon Tuesday morning through Thursday morning.  This soft slab releases with a single wrist tap using the compression stress test.  The next 18 inches layer is colder, lighter snow from Sunday that releases as a soft slab with three wrist taps.  Below these new snow layers is the old snow melt-freeze crust. The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are NO significant temperature gradients in the snowpack to drive change processes.

Rain triggered D3/R3 slab avy on south aspect Bear Creek basin. 3/6/2014.

Rain triggered D3/R3 slab avy on south aspect Bear Creek basin. 3/6/2014.


Bear Creek Avalanche. Crown line is just under trees at ridgetop. 3/6/2014.

Bear Creek Avalanche. Crown line is just under trees at ridgetop. 3/6/2014.


Bear Creek Avalanche. Crown line traversed the whole head of basin for more than ¼ mile. 3/6/2014.

Bear Creek Avalanche. Crown line traversed the whole head of basin for more than ¼ mile. 3/6/2014.


Rain triggered D3/R3 slab avy on north aspect Bear Creek basin. 3/6/2014.

Rain triggered D3/R3 slab avy on north aspect Bear Creek basin. 3/6/2014.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

 

Storm Snow

We have experienced exceptional storm loading through 03/06/2014.  Rain triggered soft slab releases on old snow surfaces are common.  Normally storm slab problems persist for a couple of days, however, we have transitioned from one storm cycle to the next without break.  You can reduce your risk from storm slabs by waiting +48 hours before venturing out into the backcountry.  ALL avalanche terrain (starting zones, tracks, and run outs) should be avoided.

 


 

 Avalanche Problem #2 

Wind Slab

We have abundant wind deposits on both sides of our north-south trending ridgelines.  Over the weekend, west-northwest aspects were loaded by east-southeast winds.    Prior to that, southwest winds loaded the east-northeast aspects.  No wind transport occurred since Tuesday’s advisory due to rain impacts to snow surfaces to 6,000 feet elevation.  These locations should be identified and avoided.

 

 


TREND:  Storm loading (0.50 inches of rain) is the forecasted Saturday afternoon through Sunday.  Temperatures are forecasted to be above freezing daytime in the upper 30s, and night time in the upper 20s through Sunday. 

 


  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range continues to be HIGH.  This means that very dangerous avalanche conditions exist on many terrain features, such as steep semi open slopes.  Natural avalanches are likely, and human triggered avalanches are very likely.  Backcountry travel in ANY avalanche terrain is NOT recommended.

SPECIAL NOTE:  Thursday morning, rain triggered natural slab releases were common in the East Cabinets.  Approximately 60% of north aspect chutes released and 40% of south aspect chutes.  They started near ridgelines at approximately 6,000 feet and ran as D3/R3 avalanches.  This means they could bury/destroy a car and involve approximately 80% of the historic avalanche path.  There is still significant “hang fire” slab material left out there!  


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

 

Kootenai National Forest Avalanche Advisory – 3/4/2014

THIS ADVISORY HAS EXPIRED.

The avalanche information for the Kootenai National Forest is provided by Kootenai National Forest personnel. The Flathead Avalanche Center hosts this information on its website for the Kootenai National Forest.

Issued: March 4, 2014 at 7:00 a.m. by Jon Jeresek
Expires: 11:59 p.m. of issue date

This advisory applies only to backcountry areas outside established ski area boundaries. The next scheduled advisory for the Kootenai National Forest area will be Friday, March 7, 2014 by Jon Jeresek.


MOUNTAIN WEATHER 

WeatherGraphic

Since the Friday AM (February 28th) advisory, HEAVY amounts of snow (SWE 0.7”- 2.3”) have fallen at Kootenai snotel sites (Banfield Mtn, Bear Mtn, Hawkins Lake, Poorman Cr).  Winds Friday through Saturday were from the east-southeast and strong with HIGH snow transport.  Temperatures at all sites have been below freezing for the last four days till noon Monday.  There is abundant soft snow available for wind transport at all sites in our Ranges.

FORECAST:  Cloudy skies Tuesday through Thursday.  All daytime temperatures are forecasted to be just above freezing, with night time temperatures in the upper 20s.  Winds will be out of the southwest at 10 – 21 mph with HIGH probability of snow transport Tuesday through Thursday.  Chance of snow is 80 – 100% Tuesday AM through Thursday, with VERY HEAVY accumulations of 19” – 29” forecasted.


 RECENT OBSERVATIONS

RecentObservationsGraphic

We traveled to Horse Mountain in the East Cabinets located 17 air miles south of Libby on March 3rd.  75” to 80” of snow was encountered on West aspects at 5,300’ elevation.  The top 20” of the snowpack consists of heavy new snow from Monday overlaying colder, lighter snow from Sunday.  Below this new snow is a knife hard suncrust from Tuesday-Wednesday that overlays a cold, soft snow layer. Below these surface layers are hard slabs which release cleanly with moderate force.  The base of the snowpack shows depth hoar development as a result of the severe temperature gradients during the first week of February.  Currently, there are NO significant temperature gradients in the snowpack to drive change processes.

Road to Horse Mtn showing roller ball activity. 3/3/2014.

Road to Horse Mtn showing roller ball activity. 3/3/2014.


Cable Mtn 6,000’ showing soft slab natural releases. 3/4/2014.

Cable Mtn 6,000’ showing soft slab natural releases. 3/4/2014.


Front of the East Cabinet Range. 3/3/2014.

Front of the East Cabinet Range. 3/3/2014.

 

 

 

 

 

 

 

 

 


 

  SNOWPACK DISCUSSION

Avalanche Problem #1

 

Storm Snow

We have experienced exceptional storm loading through 03/03/2014.  Soft slab releases on old snow surfaces are common.  Normally storm slab problems persist for a couple of days, however, we have transitioned from one storm cycle to the next without break.  You can reduce your risk from storm slabs by waiting +48 hours before venturing out into the backcountry.  ALL avalanche terrain (starting zones, tracks, and run outs) should be avoided.

 


 Avalanche Problem #2 

Wind Slab

We have abundant soft snow available for wind transport.  Over the weekend, west-northwest aspects were loaded by east-southeast winds.  Southwest transport winds of 12 -21 mph are forecasted through Thursday.  This will result in wind slabs and pillows on east aspects.  Our dilemma is that both sides of our north-south trending ridgelines have been recently loaded.  These locations should be identified and avoided.

 

 

 


 TREND:  VERY HEAVY storm loading (19” – 29”) in the forecast through Thursday.  We expect HIGH wind transport (SW 12 -21 mph) of available snow Tuesday through Thursday.  Temperatures are forecasted to be just above freezing daytime, and night time in the upper 20s through Thursday.  The trend is for RISK TO INCREASE through this period. 


  BOTTOM LINE

The avalanche hazard in the West Cabinets, East Cabinets and Purcell Range continues to be HIGH.  This means that very dangerous avalanche conditions exist on many terrain features.  Natural avalanches are likely, and human triggered avalanches are very likely.  Backcountry travel in ANY avalanche terrain is NOT recommended.

SPECIAL NOTE:  Last Tuesday-Wednesday we observed consolidation and some strengthening of the snowpack on solar slopes (south and west aspects).  This was followed significant wind transport Friday-Saturday with east-southeast winds loading west-northwest aspects.  This wind event was accompanied by very frigid temperatures.  Finally, Sunday-Monday produced significant storm loading with natural releases common.  This loading event came in cold and finished warm creating inverted snowpack densities.


 DISCLAIMER

This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.