Avalanche Forecast

Issued: Nov 26th, 2020 8:16AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Persistent Slabs.

ross campbell,

Glacier.

Thanks to everyone for the MIN posts. Human triggered avalanches are likely in steep unsupported terrain features today, and if the sun does poke out today, give solar paths like frequent flyer a wide berth.

Summary

Weather Forecast

Another mixed bag of weather conditions today; expect, flurries with sunny breaks, southerly winds gusting to moderate, and the FL hovering near 1000m.

Tonight: Flurries, FL 700m, mod SW winds.

Friday: 6cm of new snow, Mod-strong SW winds

Saturday: 10cm of new snow, strong SW winds

Snowpack Summary

10cm overnight + the 30cm on Tuesday evening brings our storm total to 40cm at TL; This new snow accompanied by Mod-Strong southerly winds formed storm slabs in the alpine and exposed terrain features @ TL. The Nov 5th crust complex (3-10cm thick) is now buried over 1m deep and can be found up to 2500m on all aspects; with facets above and below.

Avalanche Summary

Approximately 20 new Natural Avalanches were observed in the HWY corridor yesterday. The majority were size 1.5-2, with a couple of size 3s; Most of these slides were in very steep terrain off of Mt. Mcdonald, and Mt Tupper. No reports from the backcountry yesterday, but suspect there was some natural activity yesterday and last night.

Confidence

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

Problems

Storm Slabs

40cm of storm snow in the last 48 hours combined with Mod-Strong SW winds have built storm slabs in the Alpine and exposed terrain features at TL. Be mindful of terrain features that have seen significant loading, where storm slabs are lurking.

Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.
Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Persistent Slabs

Steep planar slopes should be avoided, especially at and just above treeline.

Recent natural/human triggered avalanches, snowpack tests, and reports of whumphing indicate that this layer may still be triggered by the weight of a skier.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Nov 27th, 2020 8:00AM