Avalanche Forecast
Issued: Feb 21st, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Storm Slabs.
Adam Greenberg,
If you decide to brave the blizzard, avoid avalanche terrain. Warming, wind, and new snow are forming slabs over a layer of weak facets. These will be reactive in unusual places at lower elevations including in the burnt forest.
Summary
Weather Forecast
Sunday night through Monday will bring blizzard conditions with strong to extreme westerly winds and anywhere from 20-40cm of new snow. Models vary on freeing levels which could peak anywhere from 1400 to 1800m Monday night. Tuesday and Wednesday will see progressively cooler conditions and clearing skies with wind continuing out of the west.
Snowpack Summary
Extreme southwest through westerly winds continue to build wind slabs over a weak facet layer on top of older facetted snow. In lower elevations, this sits on a hard crust increasing the potential for wide propagations. Midpack is made up of facets and decomposing crusts of varying resistance. Thin snowpack areas are very facetted.
Avalanche Summary
A natural Size 2 avalanche with a 40cm crown was seen on a crossloaded west aspect well below ridgetop at 1900m triggered by extreme winds on Sunday. It likely failed on a layer of facets. Visibility was poor, but forecasters suspect several other similar failures in the forecast region.
Confidence
Problems
Wind Slabs
Wind slabs will be found at all elevations including in the burnt forest, and may propagate farther then expected due to underlying facet layer. This is especially true at and below treeline where the facets are sitting on a hard melt freeze crust.
- Be aware of the potential for wide propagations which could result in large avalanches.
- Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Expect to find reactive storm slabs in sheltered areas. These could be especially touchy in lower elevation areas where they are sitting on facets above a melt freeze crust.
- Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.
- Be aware of the potential for wide propagations.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Feb 24th, 2021 4:00PM
