Date issued

Jan 19, 2018 - 4:00 PM

Valid until

Jan 20, 2018 - 4:00 PM

Prepared by

max darrah

Ski quality has improved with the new snow. Careful slope evaluation is essential right now to assess whether or not this new snow is sitting on a well preserved surface hoar layer in the top 15cm of the snowpack.

Regular season
Saturday - January 20, 2018
Alpine

3 - Considerable

Dangerous avalanche conditions. Careful snowpack evaluation,cautious route-finding and conservative decision-making essential.

Natural avalanches possible;human-triggered avalanches likely.

Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.

Treeline

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Below Treeline

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

Sunday - January 21, 2018
Alpine

3 - Considerable

Dangerous avalanche conditions. Careful snowpack evaluation,cautious route-finding and conservative decision-making essential.

Natural avalanches possible;human-triggered avalanches likely.

Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.

Treeline

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Below Treeline

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

Monday - January 22, 2018
Alpine

3 - Considerable

Dangerous avalanche conditions. Careful snowpack evaluation,cautious route-finding and conservative decision-making essential.

Natural avalanches possible;human-triggered avalanches likely.

Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.

Treeline

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

Below Treeline

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

Avalanche Problem 1: Wind Slabs

What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?

5-10cm of storm snow has been pushed into fresh windslabs. The concern is for areas where these slabs overlay a couple layers of surface hoar in the top 30cm of the snowpack. Field teams found touchy new slabs in the Hilda Creek drainage.

Travel and Terrain Advice
  • Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.
  • Use caution in lee areas. Recent wind loading has created fresh slabs.

Avalanche Problem 2: Persistent Slabs

What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?

There are 3 distinct surface hoar layers in the top 40cm of the snowpack. These layers are expected to become more reactive to natural and human triggers with the additional snow load leading into the weekend.

Travel and Terrain Advice
  • Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.
  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Avalanche Summary

Limited visibility, but field teams report several natural slab avalanches to sz 2, originating in the alpine and running to the bottom of the track. The Jan 7 surface hoar layer was reactive to skier traffic, and ski cutting produced numerous sz 1 wind slabs in the Hilda Creek area. More activity is expected on the Jan 7 layer over the next while.

Snowpack Summary

10cm of new snow has been pushed around by recent moderate SW winds, forming new windslabs in the alpine. This new snow covers a couple interesting surface hoar layers in the top portion of the snowpack - Jan 7 (5-10mm well preserved) and Jan 17 (2-5mm). These layers may present a touchy interface for new windslabs and storm snow.

Weather Forecast

Snowfall amounts tapering off steadily, with only light scattered flurries expected through the weekend, perhaps adding another 5-10cm. Alpine temperatures will continue to cool, dipping down to -15C. Winds decreasing and returning to the light range, gusting moderate from the Southwest.

Danger Ratings Explained

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

3 - Considerable

Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

Natural avalanches possible; human-triggered avalanches likely.

Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.

4 - High

Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

Natural avalanches likely; human-triggered avalanches very likely.

Large avalanches in many areas; or very large avalanches in specific areas.

5 - Extreme

Avoid all avalanche terrain.

Natural and human-triggered avalanches certain.

Large to very large avalanches in many areas.

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