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

Dec 14th, 2019–Dec 15th, 2019

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

Regions

Sea To Sky.

An unusually shallow snowpack exists in the region right now. A persistent slab problem has been responsible for many recent avalanches, and test results suggest that this layer could propagate widely, resulting in large avalanches. Conservative terrain selection is advised.

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

SATURDAY NIGHT - Cloudy with clear periods / light northwest winds / alpine low temperature near -9

SUNDAY - Cloudy with sunny periods / northwest wind 15-30 km/h / alpine high temperature near -8

MONDAY - Cloudy with scattered flurries, up to 5 cm / southwest wind, 20-40 km/h / alpine high temperature near -5

TUESDAY - Flurries, 10 cm / southwest winds, 40-70 km/h / alpine high temperature near -2

Avalanche Summary

There were no new avalanches reported on Saturday, however the presence of a persistent slab calls for caution. Persistent slab avalanches can be tricky to predict.

On Friday, there were several reports of natural, human and explosives triggered avalanches up to size 2. The majority of these avalanches released on a persistent weak layer that was buried in mid November.

On Thursday, there were several reports of human and explosives triggered avalanches up to size 2. Some of these avalanches stepped down to a weak crust/facet layer that was buried in mid November.

No new avalanches were reported on Wednesday.

Snowpack Summary

15-25 cm of recent fresh snow likely sits on a weak layer of surface hoar in some areas, as well as sugary faceted snow. 

There is a persistent weak layer from mid November that consists of a crust/facet combination, that is now down approximately 35-70 cm. This layer has been responsible for several recent avalanches. Snowpack tests consistently indicate that this layer can be triggered by humans and propagate widely, resulting in large avalanches. 

The snowpack is unusually shallow and weak for the Sea to Sky region. Snowpack depths range between 80-200 cm and taper quickly at lower elevations.

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.