Avalanche Forecast

Issued: Mar 17th, 2020 5:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Loose Wet, Wind Slabs and Persistent Slabs.

Avalanche Canada MBender, Avalanche Canada

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A ridge of high pressure has set in for the forecast period. Expect to see mainly sunny skies. Minimize exposure to steep slopes facing the sun during the hottest part of the day.

Summary

Confidence

High - Confidence is due to a stable weather pattern; little change is expected for several days.

Weather Forecast

TUESDAY Night: Mostly clear, light northwest wind, alpine temperature -8 C.

WEDNESDAY: Mix of sun and cloud, light northwest wind, alpine temperature -5 C, freezing level 1400 m.

THURSDAY: Mix of sun and cloud, light to moderate west wind, alpine temperature -6 C, freezing level 1400 m.

FRIDAY: Mix of sun and cloud, light northwest wind, alpine temperature -4 C, freezing level 1600 m.

Avalanche Summary

Avalanche activity on Monday was reported as natural loose dry or loose wet avalanches size 1-2 running in steep terrain facing the sun in the alpine.  

Reports from this weekend show several natural wind slab avalanches ranging in size from 1.5 to 3 running in the alpine on northeast, south and southeast aspects at treeline and in the alpine. There were also several cornice failures on northerly aspects to size 2.5.

Snowpack Summary

Recent moderate to strong northeast wind has created widespread wind effect in exposed terrain. With recent sun and relatively warm temperatures expect to find either moist surface snow or crust on slopes facing the sun. 30-50 cm of new snow from last week may sit on a surface hoar layer and a sun crust on steep solar aspects. 

A widespread weak layer of surface hoar buried at the end of February is 60-100 cm deep. On solar aspects, this layer may sit over a crust. There is a low likelihood of triggering an avalanche on this layer, but the consequences of doing so would be high. Read more about surface hoar on our forecaster blog.

Terrain and Travel

  • Minimize exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
  • Be aware of the potential for large avalanches due to the presence of buried surface hoar.
  • Cornices become weak with daytime heating.

Problems

Loose Wet

An icon showing Loose Wet

Expect loose dry or wet avalanches to run in steep terrain facing the sun during the heat of the day.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs

Recent moderate to strong wind blowing from a variety of directions has formed wind slabs on all aspects.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A weak layer of surface hoar is buried 60-100 cm deep. The distribution of this problem extends to all aspects and elevations, but north to east aspects near treeline have been a hot-spot for reactivity.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3.5

Valid until: Mar 18th, 2020 5:00PM

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