Avalanche Canada jsmith, Avalanche Canada

South Rockies Avalanche Forecast

Apr 11th, 2018 5:32PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs and Loose Wet.

Forecast new snow and wind are expected to create fresh wind slabs reactive to human triggers.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY: 5-10 cm new snow. Moderate southeasterly ridgetop winds. Freezing level around 1300 m.FRIDAY: Mix of sun and cloud. Moderate westerly ridgetop winds. Freezing level rising to around 1900 m.SATURDAY: Mix of sun and cloud. Strong southwesterly ridgetop winds. Freezing level around 1900 m.

Avalanche Summary

No new avalanches were reported in this region on Tuesday.

Snowpack Summary

Rising freezing levels have caused the recent 10-15 cm of storm snow to become moist up to about 2000 m, with minimal overnight re-freeze. Below 1400 m in some areas, rain has soaked the snow surface.Multiple crusts exist within the top 100 cm of the snowpack. Some parts of the region may have a surface hoar layer roughly 60 cm deep on north aspects at treeline.A well settled midpack sits above sugary facets in many parts of the region, especially thin snowpack areas.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 1.5
New snow and wind will form thin slabs in leeward areas near ridge crests and convex features. These slabs may be touchy were they sit on a recent crust.
Use caution when transitioning into wind effected terrain.Avoid areas that look freshly loaded with snow; especially convex features below ridgetops.Avoid shallow, rocky areas where the snowpack transition from thin to thick.

Aspects:

North, North East, East, South East, South.

Elevations:

Alpine, Treeline.

Loose Wet

An icon showing Loose Wet

Likelihood

Possible

Expected Size

1 - 2
Rising freezing levels and daytime warming have been triggers for recent large, loose wet snow releases. Once moving, a loose, wet release may have the potential to trigger a slab on a deeper weak layer.
Cornices become weak with daytime heating. Give them a wide berth from above and below.Minimize exposure to sun exposed slopes when the solar radiation is strong.Use extra caution on slopes if the snow is moist or wet.

Aspects:

All aspects.

Elevations:

All elevations.

Valid until: Apr 12th, 2018 2:00PM