Avalanche Forecast
Issued: Mar 12th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Loose Wet and Storm Slabs.
Lynnea Baker,
Freezing levels expected to hover at 1800 m for the next few days and rain is expected Tuesday. Likelihood of loose wet cycle below treeline will increase through the forecasting period.
Assess bond of new snow at higher elevations to old surfaces.
Summary
Weather Forecast
Sunday: Mainly cloudy with isolated flurries. Moderate to strong SW winds. Alpine high -3. Freezing level 1800m.
Monday: Flurries, 9 cm accumulation. Strong SW winds. Alpine high -3, low -7. FL 1400m.
Tuesday: Periods of snow, 17 cm accumulation. Moderate gusting extreme SW winds. Alpine high -3, low -7. FL 1800m.
Snowpack Summary
Extreme SW winds and warm temps have pressed surface snow and created windslabs up to 70cm deep in alpine. This overlies old windslabs and the March 3 rain crust. An additional 50 cm of settling snow over the Feb 15 crust that exists up to 2000m. Lower snowpack is well settled 1F to P. HS 250-300 cm near the continental divide.
Avalanche Summary
A Na size 2.5 wind slab avalanche was observed on Bertha peak on March 12. Several other wind slab avalanches to size 3 were reported in the park this week. As always keep those Mountain Information Network observations coming.
Confidence
Problems
Wind Slabs
Extreme winds have created hard windslabs up to 70 cm deep in alpine.
- Use caution in lee areas. Recent wind loading have created wind slabs.
- Be aware of the potential for wide propagations due to the presence of hard windslabs.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Rain is forecasted to 1800m Monday Tuesday. Steep terrain below treeline will likely see wet loose activity on the March 3 melt freeze crust. Watch for signs of pin wheeling.
- Daytime warming will weaken surface layers.
- Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood
Expected Size
Storm Slabs
Strong SW winds and 20-30 cm of snow is forecast for Monday, Tuesday. This will create fresh storm slabs that may not bond well to wind slabs. Investigate bond of new snow to old surfaces thoroughly.
- Use caution in lee areas in the alpine and treeline. Storm snow is forming slabs.
- Minimize overhead exposure during periods of heavy loading from wind.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 15th, 2022 5:00PM
