Avalanche Forecast

Issued: Feb 3rd, 2015 9:02AM

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

ghelgeson, Avalanche Canada

Kootenay Boundary.

A big change is on the way beginning Thursday. Keep your eyes peeled for small sensitive wind slabs and fast running sluff, especially if you're hunting some of the bigger trophy lines Wednesday.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

Freezing levels should begin to climb Wednesday as warm air begins to move in from the coast. I expect the freezing level to top out at 1300m Wednesday as the warmth begins to make it's presence, but it should return to Valley Bottom overnight. Looks like light variable winds at treeline with moderate west winds at ridgetop, but no significant precipitation on Wednesday. The freezing level should only climb to 800m Thursday as it snows/rains. We're expecting between 4 & 13mm of precipitation during the day with moderate SW winds at treeline and strong SW winds at ridgetop. The current timing shows the warm air coming in with a vengeance Thursday night which should push the freezing level to 2000m overnight along with a healthy amount of precipitation (7 - 17mm) which will likely fall as rain below 2000m with the potential for 10 - 25cm of snow above treeline. By Friday winds should be screaming out of the SW with the bulk of the expected 8 -25mm falling as rain below around 2200m. Saturday looks super warm, wet and windy as well.

Avalanche Summary

New avalanche activity has been limited to minor sluffing in steep terrain.

Snowpack Summary

5 - 20 cm of new snow which was initially accompanied by moderate SW winds now sits on a widespread and mostly supportive melt-freeze crust 1 - 15cm thick that is topped by 6 - 15mm surface hoar. This combo has been reported on all aspects and elevations. The mid-January weak layer of buried surface hoar is down 25-65 cm and continues to give planar results in snow profile tests. The mid-December crust/facet/surface hoar combo found down 50 - 100cm is largely unreactive.

Problems

Storm Slabs

The new snow rests on a touchy combination of crust and surface hoar. Small but sensitive wind slabs and fast running sluffs are expected to persist for the next few days.

Be cautious as you transition into wind affected terrain.>Be cautious of sluffing in steep terrain.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

While unlikely, you may still be able to initiate an avalanche on the mid-December crust/SH interface in isolated spots where the snowpack goes from thick to thin, especially where the crust under the new snow isn't supportive.

Carefully evaluate and use caution around thin snowpack areas.>While unlikely, be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 5

Valid until: Feb 4th, 2015 2:00PM