Avalanche Forecast

Issued: Jan 17th, 2014 8:39AM

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

jfloyer, Avalanche Canada

Sea To Sky.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

The weather pattern is currently dominated by a strong upper ridge of high pressure giving dry conditions.Saturday: Slightly cooler air is expected to move into this area through the day. Alpine temperatures will become considerably cooler, although still warm in the range of 0 to 5C. Winds are expected to pick up becoming moderate SW by the end of the day. You might see the odd flurry towards the end of the day.Sunday: A cooler day with alpine temperatures around 0C. Winds should become light. Monday: Alpine temperatures once again climbing to +5 or possibly higher. Light winds.

Avalanche Summary

On Thursday a number of small moist wet avalanches were observed on solar aspects. A deeper release was noted associated with explosive control that ran on basal facets size 2.5.

Snowpack Summary

Very warm alpine temperatures have created a moist snow surface. Previous winds have scoured windward slopes and sculpted sastrugi (raised ridges of snow) in exposed areas. Average treeline snowpack depths are around 170 cm. Initially, the bond below the most recent storm snow was reported to be weak and comprised surface hoar, at least in some locations. Recent snowpack tests indicate that this layer has gained strength and it is difficult to find a shear within the top 100 cm of the snowpack.There are two lower layers that professionals area tracking near the base of the snowpack. A facet/crust combo from late November is still giving "sudden" results in compression tests and exists at treeline and alpine elevations. Facets likely still exist at the base of the snowpack, especially in areas where the snowpack was particularly shallow early on in the season. The most likely places you would find this problem is in the alpine in shallow rocky areas.

Problems

Deep Persistent Slabs

Heavy triggers such as a moist/wet avalanche or a cornice drop could step down to deeper instabilities.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Loose Wet

Warm alpine temperatures could destabilize the snow surface on all aspects but especially on SE and S aspects. Loose avalanches could trigger larger slab avalanches.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid exposure to terrain traps where the consequences of a smaller avalanche could be serious.>

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Valid until: Jan 18th, 2014 2:00PM