Avalanche Forecast

Issued: Mar 17th, 2015 8:14AM

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

Parks Canada ali haeri, Parks Canada

Freezing levels are forecast to rise and the sun effect should be strong today. Subtle changes to the snowpack are what catch backcountry riders off guard.

Summary

Weather Forecast

High pressure ridge will keep the skies mainly clear today with thin cloud forecast as the day progresses. The ridge will break down by tomorrow and we will have increasing cloudiness and rising freezing levels for Wednesday. No precipitation is expected until Thursday when a Pacific system is expected to arrive to the Interior.

Snowpack Summary

At treeline and above, pockets of wind slab up to 30cm thick formed by strong to extreme winds from last Saturday night overlie a combination of crusts, settled and faceted snow. The Feb19th surface hoar down 45cm has variable distribution. Below 1800m the surface is a crust formed by 10-15mm of rain from last Saturday depending on elevation.

Avalanche Summary

Whumphing has been observed in the Hermit area ~2000m yesterday. Two days ago skiers reported triggering a Sz 2.5 avalanche in the Ursus area 25cm deep, 150-200m wide. Lots of whumphing was observed at TL on that day in the Connaught Drainage

Confidence

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs created a few days ago remain a concern particularly combined with the warming and solar radiation that we are expected to get today. This is when they tend to become more reactive to human triggering.
Watch for whumpfing, hollow sounds, and shooting cracks.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

An icon showing Loose Wet
Watch for moist snow and loose avalanches originating from cliffs as indications of instability. At lower elevations you can probe with your pole to see how thick the crust is and determine whether it is breaking down with day time warming.
Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: North, North East, East, South East.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
A multitude of crusts and a surface hoar layer are buried within the top meter of the snowpack. These may become reactive with solar radiation as the bridging properties of near surface crusts weaken as the snowpack warms.
Be aware of the potential for wide propagations.Be aware of the potential for large, deep avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 18th, 2015 8:00AM