Avalanche Forecast

Issued: Feb 7th, 2016 4:00PM

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

Avalanche Canada Aaron Beardmore, Avalanche Canada

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Little Yoho.

Evidence of a widespread avalanche cycle in the Yoho Valley today. Windslabs remain very touchy. Stick to low angle moderate terrain and move through the mountains conservatively for a few days yet.

Summary

Weather Forecast

A warming trend will influence the forecast region starting mid week. It is unknown at this point as to how much the trend will affect the snowpack. Until then expect continued moderate to strong at high elevations with little to no precipitation.

Snowpack Summary

Wind slabs exist in the alpine and at tree line that are easy to trigger. The Jan 6 surface hoar/facet/sun crust layer, down 40-100cm, is becoming less reactive to skier triggering, however sudden collapse results persist on the Jan 6 and Dec 3 layers. Isolated whumphing on mid-pack facets/surface hoar have been observed this past week.

Avalanche Summary

A major avalanche cycle occured on Saturday (Feb 6). Many slabs up to size 2.5 were observed throughout the Yoho Valley today. Cornices appear to be fragile due to the strong wind yesterday.

Confidence

Timing or intensity of solar radiation is uncertain on Wednesday

Problems

Wind Slabs

An icon showing Wind Slabs

New snow and very strong wind on Saturday have created touchy wind slabs in the alpine. These slabs are still very susceptible to human triggering.

  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs

An average of 40-100 cm overlies the Jan 6 layer of surface hoar, facets and sun crust. Test results on this layer show it has become stubborn to trigger, but potential for wide propagation remains. The new snow will increase the likelihood of this.

  • Use careful route-finding and stick to moderate slope angles with low consequences
  • Avoid open slopes and convex rolls where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Feb 8th, 2016 4:00PM

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