YESTERDAY:
Monday January 11, 2021. Sunrise was at 08:08 Hrs. -2 with a 20-40 KPH SE wind.Monday Jan 11, 2021. 15:00 Hrs. -2 with a 15-25 KPH ESE wind. +3 in the valley.
2240 meters -3, Winds were 95-115 KPH SE--Horstman Hut
1860 meters -1, Winds were 30-50 KPH S --Rendezvous
1570 meters -2, 10 cm in 12 Hrs, 20 cm in 24 Hrs, Base 169 cm--Catskinner
FORECAST:
Frontal band will bring periods of light to moderate precip and strong wind in a South Westerly flow aloft. Some models have the FL rising to 2000 meters. Some 1600 meters. There is warm air aloft already. The atmospheric river event went South yesterday just brushing the area, we might have a repeat today. The front should pass by Wednesday morning with a ridge building Wednesday afternoon. Unsettled in the morning with sunny weather in the afternoon. Thursday will see some clouds move in with a mix of sun and cloud. Guesstimates: 30-45 cm above 1800 meters by Wednesday am, 0-trace by Thursday am, 2-4 cm by Friday am.
AVALANCHE ACTIVITY:
Sz 1 from snowmobile cliff drop. 1650 m on Rainbow yesterday. Toby Salin image.Two ski tourers injured on Republican Mountain, Montana. Article below. GNFAC Image
Avalanche Summary
On Monday reports from avalanche control using explosives saw up to size 2 slab avalanches on slopes below cornice failures.
Natural avalanche activity is expected on Tuesday during the storm. The snowpack is complex right now and it's a good time to wait out the storm before venturing into avalanche terrain.
A large (size 3) avalanche was remotely triggered by skiers on Cowboy Ridge near Whistler on Saturday. The avalanche occurred on a north to northwest aspect at around 1900 m. The crown ranged reached up to 200 cm and was approximately 200 m wide. Check out this MIN for photos and more information. A similar avalanche was remotely triggered by skiers on a nearby westerly slope on Thursday; check out this MIN for more info and photos.
These avalanches are clear evidence that the weak layers described in the Snowpack Summary are still triggerable by riders and the consequence of being caught would be high.
Otherwise, small storm and wind slab avalanches were triggered by riders and naturally on Saturday and Sunday, generally 10 to 30 cm deep, on north to northwest aspects, and at treeline and alpine elevations.
Snowpack Summary
New and reactive storm and wind slabs will continue to build Tuesday. The storm is expected to drop around 15 cm Monday night and another 20-30 cm Tuesday. The storm will come with strong southwest wind so wind slabs are expected at higher elevations. Treeline and below treeline elevations may see a loose wet avalanche cycle where the precipitation falls as rain.
The snowpack is currently quite complex. Numerous layers of surface hoar may be found in sheltered terrain in the top 100 to 150 cm. The area of greatest concern is around 100 to 200 cm deep, where surface hoar or sugary faceted grains may sit above a hard melt-freeze crust from early December. There have been several recent large natural and human-triggered avalanches on this layer, particularly around Whistler and Pemberton.
Near the base of the snowpack there may be faceted grains above a crust from early-November, which was identified as the failure layer in recent sporadic large avalanche releases.
INFORMATION & OBSERVATIONS:
The big event yesterday went to our South. 8.6 mm recorded in Whistler. 31.2 mm in Squamish.LOCAL AVALANCHE CANADA MIN REPORTS:
Stoop Chutes Snowpack test: Jan 10, 2021
Slide on Tricouni: Jan 11, 2021
AST-2 Oboe Basin: Jan 11, 2021
Mt Sproatt: Jan 11, 2021
Round Mountain Snowpack: Jan 11, 2021
VIDEOS:
Skier captures avalanche : Alaska
Buried snow biker tells his story: Utah
Whistler Powder Picker, Jan 11, 2021: David Jones
ARTICLES:
Experts urge extreme caution as beginners flock to B.C. Backcountry amid high avalanche risk: CBC News
Two Ski Tourers injured in avalanche: Montana
Airbag saves rider near Mount Wagner: Wyoming
Avalanche fatality was the fourth on same slope in 16 years: Utah
3 Ski Tourers caught, 1 injured in an avalanche on Belledonne Massif: France
Persistent Weak Layers: PWL
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