Archived

Avalanche Forecast

Mar 17th, 2015–Mar 18th, 2015

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

1: Low

The avalanche danger rating below treeline will be low

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

1: Low

The avalanche danger rating below treeline will be low

Regions: Glacier.

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.

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

Avalanche Problems

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

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

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