Avalanche Forecast
Issued: Dec 19th, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
An intense winter storm is delivering heavy snowfall and strong winds. Widespread avalanche activity is expected. Avoid avalanche terrain.
Summary
Confidence
Weather Forecast
THURSDAY NIGHT - Periods of snow, 15-25 cm / southwest wind, 30-60 km/h / alpine low temperature near -9
FRIDAY - Snow, heavy at times, 20-40 cm / southwest wind, 40-80 km/h / alpine high temperature near -4 / freezing level 1500 m
SATURDAY - Snow, heavy at times, 15-25 cm / southwest wind, 40-80 km/h / alpine high temperature near -4 / freezing level 1500 m
SUNDAY - Cloudy with sunny periods and isolated flurries / southeast wind, 10-20km/h / alpine high temperature near -8
Avalanche Summary
A widespread natural avalanche cycle is expected on Friday due to heavy snowfall, warm temperatures and strong to extreme winds.
Preliminary reports from Thursday suggest that an avalanche cycle was ongoing with reports of natural, explosives and human triggered avalanches up to size 2.5.
Previous heavy snowfall resulted in an avalanche cycle on Tuesday and Wednesday. Numerous natural and human triggered avalanches up to size 2.5 were reported.
Snowpack Summary
An intense winter storm is underway in the South Columbia's with up to 25 cm on Thursday night, and another 20-40 cm expected throughout the day on Friday. This will bring total recent snow amounts to 50-90 cm.
60-120 cm of snow now sits above a widespread layer of large, feathery surface hoar crystals. With more snow continuing to accumulate above this layer over the next few days, it will likely remain very sensitive to human-triggering.
A weak layer formed in late November is now buried around 1 m below the surface. This is the layer of concern relating to the listed persistent slab avalanche problem. The weak layer may present as surface hoar, a crust, facets or a combination, depending on elevation and aspect. Below this, a variety of crusts from late October are buried deeper in the snowpack.
Problems
Storm Slabs
Intense loading from heavy snowfall and strong winds will mean that an avalanche cycle is almost certain. Avoid avalanche terrain, and don't underestimate the potential for avalanches to run full path.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
A couple of weak layers formed in late November and early December are now sitting about 1+ m below the surface. This layer may present as surface hoar, a crust, facets or a combination of those, depending on elevation and aspect.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 20th, 2019 5:00PM
