Avalanche Forecast

Issued: Feb 18th, 2020 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Forecast strong winds on Wednesday should help keep snow surfaces cool as the sun beats down, but still keep an eye on steep south aspects for signs of solar warming. Watch for fresh pockets of wind loaded snow in lee features as wind slab development resumes in the alpine.

Summary

Confidence

High -

Weather Forecast

Tuesday night: Clear. Moderate southwest wind. Alpine low -9 C. Freezing level valley bottom.

Wednesday: Sunny. Strong southwest wind. Alpine high -3 C. Freezing level 700 m.

Thursday: Mostly cloudy with isolated flurries. Moderate to strong southwest wind. Freezing level 700 m.

Friday: Flurries bringing 10-30 cm new snow. Moderate to strong southwest wind. Freezing level 800 m.

Avalanche Summary

Loose wet avalanches up to size 2 on steep solar aspects were observed on Monday. A few skier triggered storm slabs size 1-1.5 have been reported, on wind loaded features in the alpine, and running on surface hoar 40 cm deep at treeline. A natural wind slab avalanche cycle was observed over the weekend size 2-2.5.

Snowpack Summary

Recent snow has been wind loaded into thick, soft slabs in immediate lees of ridge crests at alpine and exposed treeline elevations. At treeline and below, it may sit over patchy surface hoar in wind sheltered areas or crusts on solar aspects.

A thin layer of facets that formed during the January cold snap is now about 120-170 cm below the surface while an early season crust lingers at the base of the snowpack. These layers produced a few large natural avalanches in early February but have recently been unreactive.

Terrain and Travel

  • Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
  • Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet

Problems

Storm Slabs

An icon showing Storm Slabs

Natural activity has largely slowed down since the weekend but storm slabs may remain reactive to human triggers in wind loaded pockets in the alpine and where recent snow sits over surface hoar around treeline.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 19th, 2020 5:00PM

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