Avalanche Forecast
Regions:
Fresh storm slabs will likely be reactive on Monday. Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Confidence
Moderate
Avalanche Summary
We are still waiting on observations from the weekend's storm. We are expecting a natural storm slab cycle to have run during the peak of the storm and we wouldn't be surprised to see evidence of large, persistent avalanches in the clearing weather on Monday.
In the White Pass area on Saturday, a rider triggered a cornice fall from a distance, which produced a size 3 persistent slab avalanche on a northeast aspect at 1750 m. The avalanche was 200 cm deep and was suspected of having failed on a layer of facets above a crust buried in January.
Observations are limited at this point in the season, please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.
Snowpack Summary
30-40 cm of new snow has likely seen some redistribution by southerly winds, forming deep deposits in leeward terrain features. The new snow sits over previously wind-affected snow on north and east-facing slopes and a crust on windward south-facing slopes.
A weak layer of surface hoar/crust/facets buried in early January is now buried well over 1 m deep. This layer has produced recent avalanche activity in the White Pass region and remains a concern in terrain where the snowpack is thin. The lower snowpack consists of basal facets, particularly in shallow areas.
Weather Summary
Sunday night
Snowfall tapering, 5-10 cm accumulation. Moderate southerly winds. Alpine low -8 C.
Monday
A mix of sun and cloud. Light to moderate southwest winds. Alpine high -7 C.
Tuesday
Mostly sunny. Light southwest winds. Alpine high -6 C.
Wednesday
Mostly cloudy. Moderate southerly winds. Alpine high -7 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Brief periods of sun could quickly initiate natural avalanche activity.
- Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
Avalanche Problems
Storm Slabs
Fresh storm slabs will likely remain reactive Monday, especially in wind loaded lees. Avoid steep open slopes and wind loaded terrain features. The new snow may become extra sensitive to triggering upon first exposure to strong sun.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Persistent Slabs
A layer of facets sitting on a crust buried in January has recently been reactive in the White Pass area. Triggering is most likely in areas where the snowpack is thin and weak, or with a heavy load like a cornice fall or the weight of a smaller avalanche in motion triggering this deeper layer.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3