Avalanche Forecast

Issued: Apr 4th, 2014 9:51AM

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

jfloyer, Avalanche Canada

Northwest Inland.

Beware intense storms, especially the one forecast for Monday, which could combine heavy snow amounts with warming temperatures.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain

Weather Forecast

Friday night: 2- 5 cm expected overnight.Saturday: 10-15 cm new snow expected with freezing levels around 600 m. Strong winds, 50-60 km/h from the SW.Sunday: Scattered showers in the morning. Freezing levels around 600 m. Winds 30-40 km/h from the NW.Monday: Heavy precipitation. Current models are showing 15-20 mm for Smithers with 80-100km/h winds and freezing levels rising to 1500 m.

Avalanche Summary

A possible recent release was reported with few details close to Smithers on Thursday pm or early Friday. On Tuesday a steep rocky NE facing feature at 1900m released naturally resulting in a size 3 avalanche. The possibility for large avalanches appears to be still there, and the chance of one is likely to increase with anticipated warming.

Snowpack Summary

10-20 cm new snow fell on Thursday, which rests on a mix of surface hoar, small grained facets and melt freeze crusts.Previous to Thursday's snow, it was starting to feel like spring in the NW. Valley temps have been creeping into the double digits during the day, and there are reports of the top 15 cm of the snowpack regularly becoming moist with daytime heating. Previous snow falling between March 27th and 30th (15-30 cm) fell on top of a haggard old surface composed of old wind slab, melt freeze crust, and faceted old snow. I suspect the ongoing melt freeze cycles have largely healed any instabilities associated with this interface.The early March layer can be found down 75 - 100cm and is composed of facets/surface hoar on shady aspects and facets/crust on southerly aspects. The early February crust/facet/surface hoar combo is down 150 - 200cm. While it's been mostly dormant, I would not rule out the possibility of it reawakening if we see prolonged warming and/or intense sunshine.

Problems

Storm Slabs

New snow driven by strong ridge top winds has likely created touchy slabs at and above treeline. This snow is not expected to bond well to the current crust/surface hoar combo and will likely remain sensitive to human triggering Friday.

Stick to simple terrain and be aware of what is above you at all times.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Deep Persistent Slabs

Two buried weak layers exist in the snowpack. These weak layers could be activated by cornice fall, a smaller surface avalanche in motion, or a rider finding the sweet spot, which would be most likely in steep rocky terrain. Warming is also a concern

Be aware of the potential for large, deep avalanches due to the presence of buried facets and surface hoar.>Extra caution needed around cornices with current conditions.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Apr 5th, 2014 2:00PM