YESTERDAY: Happy New Year
Early Thursday am.2240 meters -5, Winds were 75-105 KPH ESE--Horstman Hut
1860 meters -3, Winds were 25-40 KPH SE --Rendezvous
1560 meters -2, 6 cm in 12 Hrs, 6 cm in 24 Hrs, Base 114 cm--Catskinner
FORECAST:
A warm front will push through this am with steady light to moderate precip in a South Westerly flow aloft. A trailing cold front will push through by this afternoon. Wet, warm, and windy weather for today with the FL possibly spiking to 2000 meters. Wishing it to rise to around 1600 meters and hover in the 1400 m range. Time will tell. Should see the winds increase just before the arrival of the cold front this afternoon. A more vigorous front for Saturday with slightly cooler temps , moderate to heavy precip and high winds. The FL will hopefully drop to around 1300 meters. By Sunday morning it dries out with unsettled weather, even a chance of some sunny breaks in the afternoon. Another frontal band arrives on Monday. Guesstimates: 30-40 cm above 1800 meters by Saturday am, 40-50 cm above 1500 meters by Sunday am, 2-6 cm by Monday am, 18-22 cm by Tuesday am.
AVALANCHE ACTIVITY:
From Sea to Sky Advisory:
Avalanche Summary
Avalanches are expected to be widespread on Friday.
At the time of publishing, there were a few reports of explosives triggered avalanches up to size 2.5. At least one of these failed on the persistent weak layer mentioned in the snowpack summary.
There was a fatal avalanche in the South Coast Inland region (near the Sea to Sky boundary) north of Pemberton in the Railroad Pass area on Monday that resulted in two fatalities. It was reported to be a size 2 persistent slab avalanche on a west aspect, around 1650 m. The RCMP press release can be viewed here, and the Avalanche Canada report can be found here.
A size 2.5 avalanche was triggered on Monday by a skier on Rainbow Mountain, which resulted in a full burial and, thankfully, a successful rescue. The avalanche failed on a 60 cm deep crust and facet layer on a northeast aspect around 1800 m.
A natural size 3 persistent slab avalanche was reported on Mount MacBeth on Monday, check out this MIN report for details of this observation.
These avalanches highlight the ongoing potential to trigger persistent weak layers in the snowpack.
Snowpack Summary
With 20 cm of new snow expected on Thursday night and another 30-40 cm in the forecast for Friday, storm slabs will be widespread.
This new snow will bring recent storm snow totals to over 100 cm.
The snowpack is currently complex, and two concerning weak layers may be present in the snowpack:
- The shallower layer, around 60 to 100 cm deep, includes feathery surface hoar crystals. This layer may be found in sheltered terrain features at treeline and lower alpine elevations, but has been reported as spotty across the region.
- The more widespread weak layer includes sugary faceted grains that sit on top of a hard melt-freeze crust. This layer ranges in depth from 20 cm to 120 cm due to the wind scouring and loading the snow in different terrain features over the past two weeks. The layer has been reported as being widespread up to around 2000 to 2200 m.
There have been several recent human triggered avalanches on these layers.
INFORMATION & OBSERVATIONS:
LOCAL AVALANCHE CANADA MIN REPORTS:
Natural avalanche & whomping on Paul Ridge: Dec 30, 2020
Sky Pilot Trees: Dec 31, 2020
Decker: Dec 31, 2020
Cayoosh: Dec 31, 2020
VIDEOS:
Powder Picker Dec 31, 2020: David Jones
Tree Well Rescue: South Chilcotins
ARTICLES:
A ski tourer has died after falling into a tree well in the Brandywine area: Sea to Sky Backcountry
Snowboarder rescued after avalanche on Mount Washington: Vancouver Island
Snowboarder falls into a sinkhole in Sea to Sky Backcountry: Winter Adventure Warning
Large Remote Triggered Persistent Slab: CBAC
The bittersweet rise of the backcountry: Colorado
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