Observation – 3/12/2014 – Canyon Creek/Half Moon, Whitefish Range

 

 

Date: 03-12-14

Time:1000 to 1500

Name: Adam Clark

DAILY FIELD WEATHER SUMMARY

ZONE: Canyon Creek, southern Whitefish Range

MT RANGE: Whitefish

ELEV. RANGE: 5000-6800

SKY

PRECIP

Type/Rate

Temperature

RIDGETOP WIND (mph) (actual or est)

HN24 est @ Elev.

HS est @ Elev.

Trailbreaking/Riding Conditions

Skiing/Riding Quality

AM

PM

AM

PM

Hi

Low

Speed

Dir

0

2-3m above 6000’

See below

See below

FEW

CLR

NO

NO

40’s

F

20’s

F

calm

NA

                             

 

Weather Comments

SKY: Cloud cover, Trend, Timing:Few clouds in am, then totally clearing by afternoon.

 

PRECIP: Type/rate, Accumulation:No new precip since Monday (3/10)

 

WIND: speed/direction/blowing snow:Calm winds today, little evidence of wind transport with the snow that fell Monday.

 

SNOWPACK AND AVALANCHE FACTORS

SNOW SURFACE: (crusts, soft snow, hard snow, dry, wet, sfc hoar):1-2cm sun crust found on the surface on southerly aspects in the AM.This began to melt and soften after noon.Below this was 15-20 cm of powder sitting on top of a thick (6cm rain crust).We found some scattered surface hoar that formed overnight, but this was getting destroyed by the sun in the PM. We mostly skied the northern aspects above Canyon Creek and found 15-20 cm of powder on top of the same 6cm rain crust found earlier on southerly aspects.This made for mostly great skiing, but tough skinning because the crust was supportable.Setting the skin track was a challenge, with much side-slipping downhill.

 

LAYERS OF CONCERN?In the afternoon, I was most concerned with the newest (Monday’s) storm snow sitting on top of the rain crust.On southerly aspects this was sliding (see photos) easily, sometimes a few hundred feet and entraining enough snow to knock a person off their feet and/or injure them.These slides made heavy, wet debris.

 

RECENT AVALANCHE ACTIVITY/OBSERVATIONS: Several wet, loose snow avalanches on southerly aspects (photos).We saw the crown line on the large avalanche in Skook Chutes that crossed Canyon Creek Road on Sunday.We also saw another crown (photo) on a NW aspect on the peak directly east, across the creek from the area known as “Big Slide”.We assume this slid earlier in the week during the Sunday rain event.

 

STABILITY TEST?We released multiple dry, loose sluffs while skiing on the northerly aspects on slopes greater than 30°.We also ski triggered wet loose avalanches (D1) on southern aspects around 1-2 PM.

 

Avalanche Observations

NUM

SIZE

LOC

TRIGGER

 

TYPE

INC

ASP

ELEV

COMMENTS:

(Est. Depth, Width, Failure Layer, Timing)

12+

D1, R1-3

Half Moon Slide

Both N and AS

WL

30-45

S

5800-6000’

Natural and ski cut released wet snow sluffs.Top 15-20cm surface snow (wet) was sliding easily on the last Sunday’s rain crust.

 

See photo.

1

D2?/ R??

Slope to the east, across creek from “Big Slide”

Unknown, assume natural

slab

?

NW

~6000’

 

 

 

 

 

 

 

 

 

Wet loose avalanche in Half Moon, Whitefish Range. 3/12/2014.

Wet loose avalanche in Half Moon, Whitefish Range. 3/12/2014.

 

Wet loose avalanche in Half Moon, Whitefish Range. 3/12/2014.

Wet loose avalanche in Half Moon, Whitefish Range. 3/12/2014.

 

Crown of natural avalanche from last week on a NW aspect east of Big Slide, Whitefish Range. 3/12/2014.

Crown of natural avalanche from last week on a NW aspect east of Big Slide, Whitefish Range. 3/12/2014.