Archived

Avalanche Forecast

Apr 19th, 2017–Apr 20th, 2017

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

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

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.

Solar radiation will cause surface layers to become more reactive. Lower elevation snowpack will become isothermal.

Weather Forecast

Cloudy with sunny periods and moderate S winds. Alpine temps of -2C and a freezing level of 1900m. Thursday brings scattered flurries and 5cm of snow to the alpine along with mod west wind and 1800m freezing level.

Snowpack Summary

25cm new snow in the last 48hrs with freezing levels dipping to around 1000m last night. Moist surface snow on all aspects the last couple of days with numerous moist slides in the highway corridor. Expect windslabs on lee features from earlier SW wind. Cornices failing sporadically with some triggering large avalanches. Isothermal snow below TL.

Avalanche Summary

9 moist avalanches to size 2.5 recorded in the highway corridor yesterday. Two days ago a field team reported touchy surface wind slabs on northerly lee aspects at 2200m. The 10-15cm soft slabs were easily failing with ski cuts and sliding on a temperature crust.

Confidence

Timing or intensity of solar radiation is uncertain

Avalanche Problems

Storm Slabs

Reactive surface slabs sensitive to human triggering on lee features in the alpine and treeline elevations. These slabs reside on sun or temp crusts extending well into the alpine.

Use caution in lee areas. Recent wind loading have created wind slabs.Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Loose Wet

Poor refreeze overnight with temps hovering around zero and new snow insulating the old surface. Warm temps are forecast with potential for solar radiation. Lower elevation snowpack will quickly become isothermal.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Pay attention to sluffing off cliffs and steep solar terrain, signs of a warming snowpack.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Cornices

Cornices are massive and sporadically failing. They are hard to predict and best to avoid exposure to. They have triggered large natural avalanches around Rogers Pass recently.

Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.Avoid travel on slopes that are exposed to cornices overhead.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 4