Avalanche Forecast

Issued: Jan 4th, 2018 5:18PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Weather models continue to show more rain and warming for the region with each successive model run. Despite recent warm temperatures, rain percolating through the upper snowpack may induce a round of natural avalanches.

Summary

Confidence

Low - Timing, track, or intensity of incoming weather system is uncertain on Friday

Weather Forecast

Friday looks to be a pretty funky meteorological period. The good news is that we are expected to return to a more typical stormy winter pattern. The bad news is that we have to endure some rain, perhaps even some freezing rain, before we get back to the snow on Saturday. THURSDAY NIGHT: Freezing level around 2200 m, moderate to strong southwest wind, 2 to 4 mm of precipitation expected.FRIDAY: Overcast, freezing level around 2200 m, moderate to strong south/southwest wind, 8 to 12 mm of precipitation expected.SATURDAY: Overcast, freezing level around 1000 m, light south/southeast wind, 2 to 4 mm of precipitation expected.SUNDAY: Decreasing cloud cover, freezing level around 700 m, light southeast wind, trace of precipitation expected.

Avalanche Summary

On Wednesday numerous loose avalanches to size 1.5 were reported from steep south aspects at and below treeline. On Tuesday snow balling and pin wheeling was reported from north facing aspects. On Monday several loose wet avalanches to size 1 were reported from southeast and south facing features between 1800 and 2100 m.

Snowpack Summary

On Sunday a slight crust began to form on south and southwest facing aspects as warm temperatures and sun combined to moisten the snow surface. By Tuesday the upper 5 cm of the snowpack had started to become moist, even on upper elevation northeast facing features. Last Thursday and Friday two successive storms produced 50 to 70 cm of snow with wind mainly out of the south. Time and warm temperatures have allowed this snow to settle and bond well with the underlying surface. The exception may be below treeline where there may be isolated pockets of buried surface hoar. Wind effect in the alpine has been extensive but reported wind slab avalanche activity has ceased.40 to 100 cm below the surface there is a widespread melt-freeze crust that was buried on December 15th. This layer has not produced much in the way of avalanche activity and is likely trending towards dormancy. Beneath the mid-December crust, the lower snowpack is generally strong and well settled.

Problems

Storm Slabs

An icon showing Storm Slabs
Rain is expected Thursday night and Friday to at least 2200 m. The most dramatic effect will likely be on higher elevation north facing slopes, but prolonged rain could initiate widespread natural avalanches on all aspects and elevations.
Avoid avalanche terrain during periods of rain.The first few hours of rain on snow are often the most dangerous.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 5th, 2018 2:00PM