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Archived

Avalanche Forecast

Apr 15th, 2012–Apr 16th, 2012
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold
Alpine
Below Threshold
The avalanche danger rating in the alpine will be below threshold
Treeline
Below Threshold
The avalanche danger rating at treeline will be below threshold
Below Treeline
Below Threshold
The avalanche danger rating below treeline will be below threshold

Regions: Northwest Inland.

We are no longer issuing Danger ratings for this region. Most professional operators are finished for the season, and observations are very limited. Avalanche problems are listed for spring conditions.

Weather Forecast

Avalanche Summary

As we transition into spring the surface layers have a great deal of influence on the snowpack. When there is a solid re-frozen surface crust, travel is fast and easy, and the snowpack is held together by the surface cap. Any deeper persistent weak layers are unlikely to fail until the surface cap breaks down from daytime heating. When there is no crust, any deeper weak layers may fail depending on the amount of heat and the triggering force that is applied. If it cools off and snows, new snow and windslabs may not bond well to the hard spring crusts.

Snowpack Summary

Spring conditions exist in the region. Exposure to the sun, warm temperatures, and periods of rain are the most likely factors to influence the avalanche danger. If the temperatures go below freezing overnight, strong crusts should develop that are likely to hold the snowpack together. If the sun shines for a few hours, the crusts may break down quickly and moist surface snow avalanches may start running naturally. Continued warming from more sun, rain, or no overnight freeze, may cause surface avalanches to step down and trigger deeper wet slab avalanches. Prolonged warming may also weaken large and destructive cornices. It is important to monitor the temperature and the freezing levels as they may change rapidly from day to day.

Avalanche Problems

Loose Wet

Snow stability can deteriorate very quickly with warm spring temperatures. Watch for loose wet avalanches on steep terrain, especially under direct solar radiation.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 5

Wet Slabs

Snow stability can deteriorate very quickly with spring temperatures. Melt freeze crusts are common in the spring and provide ideal sliding surfaces for wet slabs. Destructive glide cracks also fall into the wet slab category.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 5

Cornices

Large cornices exist in alpine terrain. A failure could be destructive by itself, and could also trigger an avalanche on the slope below.

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 6