Avalanche Forecast

Issued: Mar 23rd, 2018 4:47PM

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

Avalanche Canada cgarritty, Avalanche Canada

More scattered convective snowfall is in the forecast, meaning slab problems will increase in some areas while glimpses of sun destabilize slab and loose snow on slopes that see sunshine.

Summary

Confidence

Moderate -

Weather Forecast

Friday night: Scattered convective flurries bringing a trace to 8 cm of new snow. Light to moderate south winds.Saturday: Mainly cloudy with continuing scattered flurries bringing 4-10 cm of new snow. Light north winds. Freezing level to 1300 metres with alpine high temperatures around -7.Sunday: A mix of sun and cloud with isolated flurries and a trace of new snow. Light southwest winds. Freezing level to 1000 metres with alpine high temperatures around - 9.Monday: Mainly cloudy with flurries developing in the afternoon and continuing overnight. Light southwest winds. Freezing level to 1200 metres with alpine high temperatures around -7.

Avalanche Summary

Thursday's reports included several smaller (size 1-1.5) wind slab and storm slab releases. These were skier triggered, ski cut, and explosives triggered. They occurred on a range of aspects at treeline and above.Reports from Wednesday were limited to small wind slab ski cuts as well as natural and ski cut loose wet releases to size 1.5. Adjacent regions have continued to show isolated small (size 1) ski cut and skier-triggered storm slabs on various aspects in the alpine. These have been failing on recently buried crust and surface hoar layers down 20 -30 cm.Reports from earlier in the week included several small (size 1-1.5) storm slabs that were ski cut and skier-triggered on steeper alpine slopes on a range of aspects. Looking forward, newly formed 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 to extreme southerly winds brought a wind-affected 10-20 cm of new snow to the region over 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 30 and 50 cm below the surface. Some potential exists for shallower storm slab avalanches to 'step down' to these deeper layers.New snow amounts taper with elevation and below 1900 m, reduced accumulations have buried a supportive crust on all aspects. Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with a surface avalanche stepping down, large 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.

Problems

Wind Slabs

An icon showing Wind Slabs
New snow will add to the reactive slabs that formed during Thursday night's storm. These slabs will likely remain primed for human triggering on Saturday while a skiff of new snow makes it trickier to pick out recent wind loading patterns.
Give cornices a wide berth when travelling on or below ridges.Be especially careful with wind loaded pockets near ridge crests and roll-overs.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 24th, 2018 2:00PM