12/8/13 Avalanche Incident–Noisy Basin, Swan Range

Noisy Basin Avalanche Incident Report

Swan Range, MT

Date of Avalanche: 8 December 2013

Date of Investigation: 10 December 2013

 

 

INCIDENT SYNOPSIS

On Sunday, December 8, 2013, a party of two skiers was traveling in the Noisy Basin area near Camp Misery in the Swan Range, MT.  At approximately 1500, both skiers were descending a slope when they tritggered and avalanche that failed approximately 100 feet above them.  Skier #1 (a 36 year old male) was caught in the avalanche, carried downslope approximately 300 to 400 feet through some trees, lost one ski, and came to rest buried up to his neck in the snow.  He sustained a broken nose, lacerations to the face that required six stitches, multiple contusions and bruises, and a minor injury to his leg.  Skier #2 (a 35 to 40 year old male)was following a few turns behind Skier #1 and was also caught in the avalanche.  Skier #2 was carried downslope, sustained an injury to his knee when one of his skis was torn off, but was not buried.  Skier #2 was able to find Skier #1 downslope and dig him out.  They called a friend via a mobile phone to come help them with a snowmobile and slowly worked their way to the road to meet him. At this point they were able to depart for the trailhead.  An attempt at a site investigation occurred on Dec. 10 by Flathead Avalanche Center staff, but the site could not be located due to new snowfall and dangerous avalanche conditions. The information contained in this report became available on December 18. The avalanche occurred on a west facing aspect within a defined avalanche path.  The reported crown depth was approximately 8 to 10 inches, with a crown width of approximately 150 feet and ran approximately 500 vertical feet.  Approximate elevation of the crown was 6400 feet and the toe of the debris was 6200 feet (Figure 1).  The United States classification of the avalanche is SS-ASu-R4-D2-U (Greene e al. 2010).

 

 

noisy_12_8_13b 

Figure 1: Avalanche location in relation to Camp Misery and 12/14/13 avalanche

 

WEATHER AND SNOWPACK

December 8 was cold and clear in Noisy Basin with winds from the north/northwest at approximately 10 to 15 mph.  The week leading up to the incident was notably cold and dry with the presence of an arctic air mass, no new precipitation and temperatures averaging -15 to -25 degrees Fahrenheit.  The last significant snowfall was over a week previous to the incident (Figure 2).  The nearest remote weather station is Noisy Basin SNOTEL site, but this site lacks a wind sensor. However, based on other remote stations in the region and field observations, winds in the 48 hours prior to the incident were generally in the 15 to 20 mph range, gusting to 30 out of variable directions that included a substantial amount of time out of the north-northeast.  The skiers reported seeing wind slabs at Picnic Notch and also seeing a good deal of scour along the ridgeline to the south of Picnic Notch. 

 

 weather

Figure 2: Air temperature, snow water equivalent (inches) and snow depth (inches) from Noisy Basin SNOTEL site (elev. 6040 ft.) from December 1 to December 8, 2013. The incident took place on December 8, 2013.

 

 

AVALANCHE

The Flathead Avalanche Center Advisory for December 8 read:

“Overall, the avalanche hazard is MODERATE.  This means that human triggered avalanches are possible particularly on steep slopes with sensitive wind slabs and in isolated areas where buried surface hoar and crust layers are more reactive.”

 

The advisory listed WIND SLABS as an avalanche problem and identified possible atypical loading patterns due to north to northeast winds. No other avalanche activity was reported in the area during this time. One snowmobiler reported wind affected snow on convex rollovers near creek beds in the area.

 

Flathead Avalanche Center Staff received a very vague report of a skier triggered avalanche the evening of Sunday, December 8, 2013.  Staff spoke to the reporting party, who had no details on location or identity of those involved.  Flathead Avalanche Center staff members attempted to locate the avalanche site on December 10, but were unable because of new snowfall and dangerous avalanche conditions.  FAC staff continued to receive ambiguous reports on the incident until they obtained contact information and were able to contact the involved parties on December 18.  All information in this report is solely based on reports from the two parties involved. Flathead Avalanche Center staff last visited this area (Noisy Basin) on Friday, December 6.

 

From information received from the two skiers involved in the incident, the crown depth was approximately 8 to 10 inches (20-25 cm) deep and approximately 150 feet (45 m) wide and the slide ran approximately 500 feet (150 m) vertically.  Elevation of the crown was approximately 6400 feet (1950 m) and the toe of the debris approximately 6200 feet (1890 m).  The United States classification of the avalanche is SS-ASu-R4-D2-U (Greene e al. 2010). Because of the inability to conduct a crown profile, we can only speculate on the snowpack at the time of the incident using information from the skiers and other observations.  We speculate that the slope had some degree of wind loading from the previous days’ north and northeast winds and that the weak layer was an interface within that wind loaded portion of the snowpack. 

 

Skier #1 (36 year old male on telemark skis without straps) and Skier #2 (35 to 40 year old male on alpine skis) parked their vehicle at the Switchback Trail (#725) Trailhead around 1200 on Noisy Basin Road and skinned up the road from there.  They had planned on a quick tour, mostly for exercise and anticipated staying mostly within treed terrain.  Skier 2 checked the avalanche advisory in the morning and both were carrying a beacon, shovel and probe.  They consider themselves accomplished skiers with a good deal of experience in avalanche terrain, but have no formal avalanche education.  They ascended to Picnic Notch, noting some wind slabs in the notch, and continued south along the ridge to the slope they descended.  They descended through the trees to the opening where the avalanche occurred, catching it downslope of their intended location.  Skier #1 entered the opening (approximately 400 yards vertical by 100 yards wide) around mid-slope and found the snow “surprisingly good” his first couple of turns.  Skier #2 followed Skier#1 closely and made two turns before he realized the snow was moving.  Skier #1 made a few turns before everything started to move.  The slope had failed somewhere above him, approximately 100 feet.  Skier #1 was caught in the avalanche, carried downslope head first and struggled to swim. Skier #1 stated that after about 5 seconds, it “felt like someone hit me with a 2×6 across the face.” He was strained through some trees at the bottom and came to a stop after another 3 to 5 seconds.  Skier #1 came to rest in an upright position, buried up to his neck after being carried approximately 300 to 400 feet downslope.  He could breathe, but not move.  He had lost one ski, of which the binding had broken (Figure 3), and both poles, but one ski remained attached.  He received a broken nose, lacerations to the face which required 6 stitches, multiple bruises and contusions, and a minor leg injury.

Skier #2 provided this account:

 “My friend dropped in first and he made a turn in soft snow that looked great. I dropped in immediately after to make some 8s. I made two turns before I realized the snow was moving too. I stayed on top as I tried to head for the trees on my right as a possible safe zone when I realized I wasn’t getting there and it would take me more into the slide. I tried to go left and my ski got yanked off and my knee popped.  I tried to stay on top with my one remaining ski when I got tossed. The snow stopped and I wasn’t buried. I checked myself for injury and looked uphill to where I last saw my partner. I called out but didn’t hear a response. I scanned uphill for equipment a hand or anything when I heard him yell. I still thought he was above me when he yelled again and said “below you, hurry”. I scooted down on my one ski and grabbed his loose ski on my way to find him partially buried and pressed against a tree. He was bloody and moving slow. I dug out his legs and took off his one remaining ski. We called family and friends that headed up jewel basin road to get us at camp misery. My friend and I each hobbled down on one leg back to the road.”

 

Skier #2 lost one ski and a GOPRO camera.  His knee has some muscle damage that will keep him from skiing for approximately a month.

 

Ski Binding 2013 Avy 

Figure 3: Broken binding on Skier #1’s telemark ski

 

We appreciate both skiers speaking with us and sharing the details of the event so that they may be used to inform and educate others.  They also shared some of their lessons learned, in their own words below:

Lessons Learned (we have all heard before but reiterate):

-Commence descent of prone areas from the start zone as opposed to mid-slope to increase ability to keep the slide/slough debris downhill and find a safe exit.

-Descend one at a time and spaced apart.     

-Route Selection-It doesn’t take a lot of snow or a large exposed slope to result in a deadly slide.  Slide occurred on small exposed gash within generally treed/gladed area.  Trees/Anchors are a good thing unless you are being strained through them. 

-Familiarity-Both skiers can access this area from their living rooms.  It is easy to get complacent, especially with minimal early season snowpack and a generally unexposed route previously skied in all kinds of varying conditions and points during the year.”

 

 

SEARCH AND RESCUE

No search and rescue operations were initiated as the skiers were able to extricate themselves and return to their vehicles with some help from a friend with a snowmobile.

Direct any questions regarding this report to fac.admin@flatheadavalanche.org or 406.261.9873.

Report prepared by Seth Carbonari and Erich Peitzsch of the Flathead Avalanche Center.

REFERENCES
Greene, Ethan M., D. Atkins, K. Birkeland, K. Elder, C. Landry, B. Lazar, I. McCammon, M. Moore, D. Sharaf, C. Sterbenz, B. Tremper, and K. Williams, 2010. Snow, Weather, and Avalanches: Observational Guidelines for Avalanche Programs in the United States.  American Avalanche Association, Pagosa Springs, CO: Second Printing Fall 2010, 152 pp.