YESTERDAY:
First lift up Friday morning.2240 meters -11, Winds were 10-20 KPH S--Horstman Hut
1860 meters -9, Winds were 15-25 KPH ESE --Rendezvous
1570 meters -6, 1 cm in 12 Hrs, 1 cm in 24 Hrs, Base 183 cm--Catskinner
FORECAST:
The weak upper trough will bring overcast skies this am with some scattered flurries ending this am. There are a few breaks in the mix as well. A warm front will arrive sometime this afternoon with light precipitation in a North Westerly flow aloft. The FL will hover around or slightly above surface. By Sunday the atmospheric river event will bring warming temps, strong winds and moderate to heavy precip. Still thinking the FL will remain below 1500 meters. The most intense precip will arrive Sunday afternoon into the night. By Monday the precip will ease to showers in the early hours of the day. Should see a break with dry cloudy conditions before a cold front arrives later in the am. Brief impulse of precip with a drying trend and cooler temps by Monday evening. At this time it looks unsettled for Tuesday with seasonal temps and some periods of light precip. Guesstimates: 8-12 cm by Sunday am, 20-30 cm by Monday am, 2-4 cm by Tuesday am, trace-1cm by Wednesday am.
GOES IR image from this am.
AVALANCHE ACTIVITY:
A snowmobiler has died in an avalanche in Idaho. Smiley Creek. Article below. Net PicSa Sz 1 Cowboy Ridge Feb 19, 2021 from MIN Report below. C Watson Image
Avalanche Summary
New wind slabs were reactive on Friday, with reports of size 1 human triggered avalanches on smaller slopes and size 2 natural and explosive triggered avalanches on bigger slopes. Between Tuesday and Thursday there were several small (size 1-1.5) human-triggered wind slab avalanches, as well as some dry loose and wet loose avalanches in steep terrain.
There was some notable avalanche activity towards the end of last week and last weekend, as a bout of strong northerly winds formed large wind slabs in unusual places (eg. south, southeast, and southwest facing slopes). This created a tricky problem that resulted in a string of serious avalanche accidents. On Feb 11 two skiers were caught in a natural wind slab avalanche in a couloir on Mamquam Mountain, resulting in serious injuries. On Feb 12, a fatal avalanche was triggered by skiers at 2200 m on a west-facing slope on Phalanx Mountain (a size 2.5 wind slab). On Feb 12, another fatal avalanche was triggered by skiers at 1700 m on a treed southwest-facing slope in the Brandywine valley (a size 1 wind slab). See the incident reports here and here for details. These wind slabs have decreased in reactivity over the past the week, however may still present as a problem with the stress of new snow and wind.
Snowpack Summary
As of Friday afternoon there is 10-20 cm of new snow above a widespread interface that may become a reactive failure layer for storm and wind slab avalanches over the weekend. This interface consists of a surface hoar layer at treeline, a crust below 1800 m, sun crusts on steep south slopes, and faceted surfaces and hard wind slabs in the alpine. Below the evolving surface, 80-120 cm sits on a lingering persistent weak layer from late January that consists of facets at upper elevations and surface hoar in sheltered areas. Although this structure is suspect, we have no recent reports of avalanches failing at this interface within the region.
INFORMATION & OBSERVATIONS:
Someone fell into a 3 meter rock hole yesterday below Pakalolo. Rescued!!!FROM SEA TO SKY MIN REPORTS:
Cowboy Ridge Sz 1: Feb 19, 2021
Brandywine Brap: Feb 19, 2021
Pauls Ridge: Feb 19, 2021
Freda Trees: Feb 19, 2021
VIDEOS:
Smiley Creek Avalanche Incident: SAC
Big Avalanche: UAC
Powder Picker Feb 19, 2021: David Jones
ARTICLES:
Snowmobiler killed in Idaho avalanche on Friday: Sawtooth Mountains
A snowboarder has died in an avalanche in Wyoming: Togwotee Mountain
Kootenay man survives avalanche and lives to tell the tale: Norns Range
Avalanche risk expected to be High this weekend in the Sea to Sky Area: Avalanche Canada
The Backyard Backcountry Challenge: Avalanche Canada Foundation
Covid-19 Tests required at Austrian Ski Resorts: SnowBrains
Snowboarders facing criminal charges for avalanche above I-70 lose a critical battle in court: Colorado
Is this years Sketchy Snowpack the new normal: Outside Magazine
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