Avalanche Forecast

Issued: Mar 25th, 2018 5:48PM

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

Avalanche Canada mgrist, Avalanche Canada

Be vigilant for lingering wind slabs at higher elevations. Use terrain features to your advantage while avoiding wind loaded pockets, and unsupported roll-overs.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Tuesday

Weather Forecast

We're looking at unsettled weather, sunny breaks and the chance of convective flurries throughout the forecast period. MONDAY: Cloudy with isolated flurries (2-5 cm possible). Moderate southwest winds 20-40 Km/hr. Freezing level to 1400 metres with alpine high temperatures of -4.TUESDAY: Occasional flurries (5-10cm). Moderate to strong west winds 25-60 Km/hr. Freezing level to 1700 metres with alpine high temperatures around -2. WEDNESDAY: Sunny with cloudy breaks. Moderate west winds 30-40 Km/hr. Freezing level 1600 metres with alpine high temperatures around -3.

Avalanche Summary

On Sunday we received reports of a skier triggered avalanche on a west aspect near 2200m in the north of the region. Also on Sunday a cornice collapse on a north east aspect near 2500m resulted in size 2 debris, but did not pull out a slab below.On Saturday, skiers were able to cut a size 1.5 wind slab on a north west aspect (crown height 10-15cm) in the east of the region. Thursday's reports included a couple of smaller (size 1-1.5) wind slabs as well as several natural size 1 loose wet releases on south aspects. The slabs were skier triggered and ski cut on north to northwest aspects in the alpine.Looking forward, newly formed wind slabs are likely to remain reactive to human triggering over the near term. Watch for intervals of solar exposure to destabilize slabs as well as promote loose wet avalanche conditions on steeper, sun-exposed slopes.

Snowpack Summary

Convective snowfall coupled with strong southerly winds brought a wind-affected 10-20 cm of new snow to the region since Thursday night. The new snow has buried a couple of recent layers of storm snow that are separated by temperature and sun crusts at lower elevations and on south aspects. Surface hoar layers have been reported between these storm snow layers on shaded aspects at higher elevations and can likely now be found at approximately 20 and 40 cm below the surface.New snow amounts taper with elevation and below about 1900 m, reduced accumulations have buried a supportive crust on all aspects. Deeper persistent weak layers from mid-late February (down 40 -100 cm deep) as well as January and December layers are generally considered dormant, but could wake up with a surface avalanche stepping down, cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. Facets also linger at the base of the snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong winds blew new snow into wind slabs that may remain reactive to human triggering on Monday. High north aspects are a special concern for the presence of buried surface hoar that could lead to easier triggering and deeper releases.
Use extra caution around high, sheltered north aspects where slabs may overlie surface hoar.Give cornices a wide berth when travelling on or below ridges.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 26th, 2018 2:00PM