Avalanche Forecast

Issued: Dec 25th, 2022 4:00PM

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

CG, Avalanche Canada

Glacier.

Here's another Xmas story...picture a large, grumpy elephant sitting on a child's tea-time table. That table is gonna burst!!

The snowpack is the tea table, the new storm snow is the elephant in the room. Natural and human-triggered avalanches are very likely.

Don't ruin tea-time today. Order a take-away bevy from the local ski hill where they'll tame the elephants as you have a lovely ski in-bounds! :)

Happy Holidays!

Summary

Confidence

Moderate

Avalanche Summary

A large natural avalanche cycle ripped through Rogers Pass Xmas Eve. Numerous avalanches from sz 2 to 3-3.5 were observed from Tupper, Macdonald, and other highway paths.

Artillery control on Xmas Day left deposits on the highway as well, with observations on Mac West Shoulder showing step-down avalanches on the persistent weak layers.

Avalanches have significant potential to increase in size once they gather up the lower elevation facets and persistent weak layers.

Snowpack Summary

Up to 55cm of new snow sits on a generally weak and facetted snowpack.

Prior to this storm the alpine snowpack was particularly thin and variable, with shallow areas facetted and unconsolidated from the snow surface to the ground.

There are several persistent weak layers buried, which are most prevalent at and near treeline. The recently buried Dec 16 surface hoar (up to 10mm) is now down ~50cm. The Dec 5 surface hoar layer is down ~70cm. The Nov. 17th surface hoar/suncrust/facet layer is down ~100cm and is the suspected failure plane for last weeks whumphing, as well as some large avalanches in neighboring areas.

Weather Summary

Remember those gross, warm, wet Holiday kisses from distant relatives? The weather gods are in the spirit of giving, and they're set to smack us all over our cheeks Monday!

Monday: 20-25cm of snow, freezing levels (FZL) rising to 1900m, winds gusting 80km/h from the SW, Alp high 0*C

Tues: 10-15cm, 1600m FZL, light ridgetop winds gusting strong, Alp high -1*C

Wed: scattered flurries, 5cm, 1300m FZL, light winds, Alp high -4*C

Terrain and Travel Advice

Continue to make conservative terrain choices while the storm snow settles and stabilizes.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Problems

Storm Slabs

Storm slabs formed rapidly on Saturday. These will require several days to settle and stabilize. Avoid avalanche terrain that has not been completely cleaned out by recent avalanche activity.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1.5 - 3.5

Persistent Slabs

There are three persistent weak layers buried in the mid-upper snowpack. All three of these layers are still reacting in the easy/moderate range in snowpack tests around treeline.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 3.5

Valid until: Dec 26th, 2022 4:00PM