Archived

Avalanche Forecast

Dec 20th, 2015–Dec 21st, 2015

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Kootenay Boundary.

Wind slabs in exposed areas and buried surface hoar in sheltered areas. Back off into simple terrain if you encounter signs of instability, like cracking or whumpfing.

Confidence

Moderate - Track of incoming weather systems is uncertain

Weather Forecast

A series of frontal systems is expected over the next three days, bringing light to moderate snow and moderate to strong SW ridge top winds. The freezing level stays near 800 m. Late on Wednesday an arctic ridge starts to build. Snowfall in the south (less in the north): Monday 5-10cm; Tuesday 10 cm; Wednesday 2-5 cm.

Avalanche Summary

No new avalanches have been reported.

Snowpack Summary

Up to 35 cm of new snow now covers the mid-December surface hoar. This surface hoar can be found on all aspects in protected areas. It is variably reactive, showing propagation likelihood around Kootenay Pass. It may become quite touchy as soon as a slab develops above it. Moderate winds out of the S/SW have recently formed fresh wind slabs on lee features. A few different crusts can be found in the upper meter of the snowpack as high as 2400m. At treeline elevation the early December crust, down 30-70 cm, is thick and supportive, and may be capping deeper weaknesses. Check out the latest conditions video at: https://bit.ly/1S2DbYb

Avalanche Problems

Storm Slabs

The combination of new snow and SW wind has created slabs on lee features near ridgetops. Below treeline, the storm slab may be extra touchy where it sits on buried surface hoar.

Avoid freshly wind loaded features and use ridges/ribs to sneak around these problem areas.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 3