Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Nov 22nd, 2020–Nov 23rd, 2020

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural and human triggered avalanches likely.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches possible, human triggered probable.

Regions

Glacier.

Do not let good visibility and great skiing entice you to ski bigger lines. The Nov. 5th crust/facet persistent weak layer is ripe for catching skiers/boarders off guard!

Weather Forecast

A weak ridge passing our area this morning will give some sunny breaks today. A system making landfall from the NW Monday will bring a moderate snowfall Tuesday.

Today: Sunny periods. Alpine High -5 C. Ridge wind (RW) light SW. Freezing level (FzL) 1300m.

Tonight: Isolated flurries. Low -7. RW light S.

Monday: Flurries. High -6. RW Light. FzL 1200m.

Snowpack Summary

Up to 70cm of storm snow over the past week, combined with S'westerly winds, has formed reactive slabs. The Nov 5th crust is now buried over 1m in most starting zones. This crust complex is over 8cm thick, and can be found up to 2500m on all aspects; with facets above and below this is an active weak layer that will persist for a long time.

Avalanche Summary

Large natural avalanches continued early Saturday morning as ongoing snowfall and wind overloaded the snowpack. These were generally initiating in the storm snow, with some stepping down to the Nov 5th crust/facet combo. There were several Min reports last week of natural, and skier triggered avalanches, as well as large whumphs in open terrain.

Confidence

Problems

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.