Avalanche Forecast

Issued: Feb 27th, 2021 8:00AM

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

jonas hoke,

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A bunch of new snow in the past couple of days, combined with the uncertainty created by the recently buried Feb. 14th interface, make conservative terrain choices your best bet for safely enjoying the epic skiing that abounds at the moment.

Summary

Weather Forecast

A brief lull from a weak ridge today, followed by more snowfall and wind as a series of fronts are pushed our way by an Aleutian Low.

Saturday: A mix of sun and cloud, Alpine High -13 C. Moderate W ridgetop wind.

Sunday: Flurries (5cm). Low -14 C, High -6 C. Moderate SW wind.

Monday: Snow (5-10cm). Low -9 C, High -7 C. Strong SW wind.

Tuesday: Flurries.

Snowpack Summary

New snow (up to 55cm) has formed fresh storm slabs over previously settled storm snow, and a thin suncrust on steep solar aspects. The 80mm of precip, and extreme S'ly winds from early in the week sit on the Feb 14 drought interface; a wind crust in exposed areas near the Pass; buried windslabs, facets, and a thin suncrust as you move East or West.

Avalanche Summary

Several storm slabs from size 1.5-3.0 were triggered by Fridays convective snowfall, most notably 2 size 3.0s from Manix and Gunners (S aspects).

A spike in wind and snow triggered several size 2-3 storm slabs on Mt Tupper and MacDonald on Thursday.

Early in the week a torrent of very large natural and controlled avalanches ran full.

Confidence

Due to the number and quality of field observations

Problems

Storm Slabs

An icon showing Storm Slabs

Up to 55 cm of new snow has formed fresh storm slabs, these will be touchier in exposed areas where they have been stiffened by the wind.

  • If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
  • The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

An icon showing Loose Dry

Expect loose dry avalanches in steep terrain. These may run quicker on steep solar aspects where they sit on a thin suncrust.

  • If triggered dry loose point releases can form deeper deposits in terrain traps.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

The 80+ cm of snow we received Monday sits on the February 14th weak layer.

This problem may persist longer in areas where the facets are well preserved, or on steep solar aspects where these is a thin suncrust at this interface.

  • Dig down to find and test weak layers before committing to a line.
  • Be wary of large open slopes that did not previously avalanche.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3.5

Valid until: Feb 28th, 2021 8:00AM