Archived

Avalanche Forecast

Nov 17th, 2018–Nov 18th, 2018

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

Regions: Glacier.

People, and the sun shining on the slopes above you, are major factors to be watching for today. And please, PLEASE, look out for rocks and other hazards just below the snow surface. It is still mid-November!

Weather Forecast

Clear, cold, and calm. Freezing levels will remain at valley bottom today, light ridge-top winds, and sunny skies. The clear skies will allow plenty of sun to hit southerly slopes. On Sunday, winds will continue to remain light, freezing levels will rise to 1300m, and cloud cover should increase. No snow is forecasted until mid-week.

Snowpack Summary

45cm of storm snow overlies surface hoar or a suncrust that has been found above 1900m up Connaught drainage and in the Asulkan hut area. Deeper in the snowpack is the October melt freeze crust. Snow depths vary from 75cm at Rogers Pass, to 150-170cm in alpine areas.

Avalanche Summary

Numerous sz 2-3 slab avalanches from N and S alpine aspects on Macdonald and Tupper were observed. These ran during the height of the storm on Nov 15th, with several reaching the valley.

Confidence

Due to the number of field observations

Avalanche Problems

Storm Slabs

45cm of storm snow has buried surface hoar on northerly aspects and a suncrust on solar aspects. These layers were active during a natural cycle 36 hours ago, are likely widespread, and were reactive in snowpack tests. Human triggering is possible.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Use caution in lee areas in the alpine and treeline. Recent storm snow has formed wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2.5

Deep Persistent Slabs

The late October crust sits near the bottom of the snowpack and is producing sudden planar and sudden collapse results. Assess this layer before committing to a line. At higher elevations a buried facet layer exists from the September snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3