Avalanche Forecast

Issued: Mar 23rd, 2018 4:52PM

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

Avalanche Canada cgarritty, Avalanche Canada

The safest and best snow conditions are likely to be found around sheltered lower elevations. Expect any appearance from the late March sun to quickly destabilize wind slabs and loose snow at the surface.

Summary

Confidence

Moderate -

Weather Forecast

Saturday: A mix of sun and cloud with isolated flurries and a trace of new snow. Light to moderate southwest winds, Freezing level to 1000 metres with alpine high temperatures around -10.Sunday: Mainly cloudy with isolated flurries and a trace of new snow, increasing overnight. Moderate southwest winds. Freezing level to 900 metres with alpine high temperatures around -10.Monday: Cloudy with continuing flurries bringing 5-10 cm of new snow, increasing overnight. Moderate to strong southwest winds. Freezing level to 1300 metres with alpine high temperatures of -8.

Avalanche Summary

No new avalanches have been reported in the Cariboos, but Thursday's reports included several wind slab and storm slab releases in the North Columbias. These were natural as well as skier triggered and ski cut, mainly from size 1 to 1.5, and occurred on a range of aspects at treeline and above.Reports from early in the week included several small (size 1) skier-triggered and ski cut storm slabs on high elevation north aspects. These slabs failed on a surface hoar layer buried earlier this month that is mentioned in our snowpack discussion, found down about 25 cm at the time. 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 5-15 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 20 and 40 cm below the surface. The deepest of these surface hoar layers was the failure plane in several slab avalanches earlier this week.New snow amounts taper with elevation and below about 1800 m, reduced accumulations have buried a supportive crust on all aspects.Persistent weak layers from early January and mid-December are still being reported by local operators. They are generally considered dormant, but could wake up with a surface avalanche stepping down, a 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
Strong winds blew new snow into wind slabs that are likely to remain reactive to human triggering on Saturday. High north aspects are a special concern for the presence of buried surface hoar that could lead to easier triggering and deeper releases.
Be cautious around high, sheltered north aspects where buried surface hoar may be preserved.Give cornices a wide berth when travelling on or below ridges.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

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

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