Avalanche Forecast

Issued: Mar 26th, 2014 9:13AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs and Deep Persistent Slabs.

triley, Avalanche Canada

Sea To Sky.

New snow may take some time to stabilise. Sunny periods may weaken the slab where it is sitting on a buried crust.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Thursday

Weather Forecast

Overnight and Thursday: Becoming overcast this evening with a chance of some convective flurries. Light Easterly winds overnight and during the day. Freezing levels dropping down to 600 metres overnight and rising up to 1300 metres during the day. Some chance of sunny periods in the afternoon.Friday: Overcast with snow starting in the morning and becoming heavy snow fall in the afternoon. Building Southwest winds becoming strong by the afternoon. Freezing levels rising up to about 1500 metres.Saturday: Snow and Southwest wind continuing. Freezing level rising to about 1700 metres.

Avalanche Summary

Reports of widespread natural avalanche activity in the top 20-30 cm of new snow up to size 2.0. Explosives control resulted in storm slab releases up to size 2.5 that were 50 cm deep. One explosive controlled cornice was reported to have released size 3.0. Some moist loose size 1.0 avalanches due to solar exposure. The new snow may take a couple of days to settle and bond.

Snowpack Summary

30-50 cm of new snow overnight that started warm and finished cold. The new snow is sitting on a mix of thin wind slabs and melt-freeze crusts on solar aspects and may not be well bonded to these old surfaces. This new snow combined with recent storm snow is sitting on a mix of facets and surface hoar on shaded aspects. The added load of storm snow or storm slab avalanches in motion may trigger the March persistent weak layer. The early-March crust/facet layer is down about 100-150 cm and the early February layer is now down close to 200 cm.

Problems

Storm Slabs

30-50 cm of new snow combined with moderate winds may take a couple of days to settle and bond to the old surface.

The new snow will require several days to settle and stabilize.>Avoid freshly wind loaded features.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

The new snow has added a new load above the buried weak layers of crusts and facets. Storm slab avalanches in motion may trigger the deeply buried weak layer resulting in very large avalanches.

Be aware of the potential for large, deep avalanches.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>Extra caution needed around cornices with current conditions.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 27th, 2014 2:00PM