Archived

Avalanche Forecast

Mar 20th, 2019–Mar 21st, 2019

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

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

Regions: Glacier.

Bust out the lawn chairs, sun hats, and iced drinks! Summer temp's have arrived for the first day of Spring. No overnight freeze last night means the hot temp's will be rapidly warming the snowpack, bringing down avalanches this afternoon.

Weather Forecast

The warm temp's this week will peak today, with alpine temp's around 8*C, light winds, and intense sunshine. Freezing levels spike at 3400m, well above the summits of the region. Much the same tomorrow, with freezing levels reaching 3200m. Clouds roll in on Friday for the weekend, with freezing levels dropping to 2200m and isolated flurries.

Snowpack Summary

A ~40cm slab exists at alpine and tree-line elevations, while isothermal conditions are present below tree-line. Surface crusts of varying hardness are prevalent on all but true North aspects in the Alpine. A second night in a row of above freezing temp's at tree-line elevation has prevented a solid crust from forming at 2000m and above.

Avalanche Summary

A large natural spring avalanche cycle started Sunday producing loose wet and slab avalanches to size 3. With no re-freeze overnight, above average temperatures, and strong solar input, the cycle is forecasted to continue through Friday. A group of 4 skiers triggered a sz 2 ascending to Mt Green, on Sunday.

Confidence

Avalanche Problems

Loose Wet

Strong sunshine and rapidly increasing temp's will destabilize the upper snowpack, resulting in loose wet avalanches during the heat of the day. Traveling in avalanche terrain is not recommended today, especially on solar aspects this afternoon.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

Aspects: East, South East, South, South West, West.

Elevations: All elevations.

Likelihood: Very Likely - Certain

Expected Size: 1.5 - 3.5

Persistent Slabs

At tree-line and above, a ~40cm soft slab is bonding poorly to the underlying sun crust, or to facets on shaded aspects. Warm temp's are peeling this slab off the mountains like a mandarin orange peel, very easily and in large pieces...

Pay attention to overhead hazards like cornices which could trigger the persistent slab.Convex features and steep unsupported slopes will be most prone to triggering.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 3