Avalanche Forecast
Issued: Mar 27th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Loose Wet.
ahanna,
Avalanche Canada
Avalanche danger will increase through the day as new snow and wind form touchy storm slabs at upper elevations and rain soaks the snowpack below 1500 m. In the west of the region where less than 25 cm of snow falls, treat avalanche danger as one step lower at all elevations.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
Highest snowfall amounts will be in the Selkirks, east of Upper Arrow Lake between Revelstoke and Nakusp.
Saturday night: 5-15 cm new snow. Southwest wind increasing 40-60 km/h. Freezing level 1600 m. Alpine temperature -3.
Sunday: 15-25 cm in the northern Selkirks, 5-10 elsewhere. 40-70 km/h southwest wind. Freezing level 1600 m. Alpine temperature -3.
Monday: Another 5-10 cm of snow by the morning then mostly cloudy during the day. 30 km/h northwest wind. Freezing level 1000 . Alpine temperature -10.
Tuesday: Mix of sun and cloud. 20 km/h northwest wind. Freezing level 1400 m. Alpine high -5.
Avalanche Summary
Avalanche activity over the past few days has primarily been small (size 1-1.5) dry loose avalanches in the top 20 cm and some small cornice failures that did not trigger any slabs. However, each day there have been a few notable slab avalanches. A natural wind slab avalanche size 1.5 was observed on Friday. On Thursday a natural size 3 avalanche was observed on a east aspect at 1800 m in the Valhallas. The crown 100 cm thick, but no other details are known. On Wednesday there was a size 2 skier triggered avalanche on a east facing slope at 2250 m in the southern Selkirks (running on a 30 cm deep crust layer).
Snowpack Summary
With 5-20 cm forecast per 12 hour period, by Sunday afternoon you could see 20 to 40 cm of fresh snow in the Selkirks and smaller amounts further west. Accompanied by strong wind, this new snow will likely form touchy slabs.
At alpine and treeline elevations, a few layers of note are buried 40-80 cm deep including a layer of small surface hoar crystals on shady, wind-sheltered aspects and a series of crusts on solar aspects and below 1800 m. Overall the snow seems to be bonding well to these interfaces, although there have been a few isolated avalanches running on crusts layer over the past few days. Lower elevations have undergone daily melt-freeze cycles, with moist or crusty surfaces likely found up to at least 1800 m.
Terrain and Travel
- Storm slab size and sensitivity to triggering will likely increase through the day.
- Dial back your terrain choices if you are seeing more than 25cm of new snow.
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
Problems
Storm Slabs
Fresh storm slabs are forming at elevations above 1500 m. Their size and likelihood will increase throughout the day as new snow falls with strong southwest wind. Natural avalanches will be very likely in the alpine and on steep wind loaded slopes at treeline.
There are also some surface hoar and crust layers in the top 50 cm of the snowpack, and while none of these layers are overly concerning, they may act as sliding layers.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Loose Wet
Loose wet avalanches are possible below 1500 m, where precipitation falls as rain.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Valid until: Mar 28th, 2021 4:00PM
