Archived

Avalanche Forecast

Apr 4th, 2013–Apr 5th, 2013

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Typical spring conditions with an overnight refreeze creating a crust on the surface of the snowpack. While the crust is strong so is your stability. Be cautious when this crust is no longer present - Strong sun today!

Weather Forecast

Clearing skies for today with freezing levels from 2000m to 2500m. A storm is predicted to begin tonight and really hit on Friday, with precipitation amounts in the 20-25mm range and warm temperatures.

Snowpack Summary

Moist snow in the snowpack has crusted over with just below freezing temperatures for a short period overnight. On due north aspects there may still be dry snow to be found at tree line and above, but yesterday a party skiing below treeline on a North aspect reported isothermal conditions and dangerous deep sluffing in steep terrain.

Avalanche Summary

3 natural moist to wet avalanches from size 1.5 to 2.5 along the highway corridor. Many recent glide crack avalanches.Numerous loose wet avalanches to size 3.0 in the backcountry on solar aspects in the last few days.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Avalanche Problems

Loose Wet

With only a gentle refreeze overnight, expect avalanche conditions when daytime heating melts the crust, and the snowpack becomes soft and isothermal. Avalanches that trigger on a shallow crust can dig deeper into the isothermal snow and get bigger.

Plan to be off big slopes before the temperatures rises and the snowpack deteriorates.Make your travel plans to take advantage of overnight freezing.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 2 - 3

Deep Persistent Slabs

Glide cracks, gaping cracks in the snowpack, exist on many slopes and have been failing with the warm temps. They can fail unpredictably, and release the entire snowpack to the ground and can be triggered by smaller shallow avalanches.

Sluffs may trigger deeper instabilities.Watch for glide cracks.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 4

Cornices

Cornices are large and unsupported. They are weak from the warm temperatures, and if they fail, may trigger deeper slabs.

Cornices become weak with daytime heating, so travel early on exposed slopes.Extra caution needed around cornices with current conditions.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 4