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Avalanche Forecast

Dec 2nd, 2016–Dec 3rd, 2016
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Sea To Sky.

The current storm is ramping up avalanche danger where new snow is accumulating. Choose conservative terrain and watch for wind loaded features.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

SATURDAY:  New snow amounts 5-10 cm accompanied by moderate westerly winds. Freezing levels to 1100 metres with alpine temperature to -6SUNDAY: Isolated flurries with moderate northwest winds shifting to northeast. Freezing levels dropping to valley bottom with alpine temperatures to -9.MONDAY: No new snow, light winds from the northeast, freezing levels dropping to valley bottom with alpine temperatures to -12.

Avalanche Summary

Fresh storm slabs are increasing the load on a weak layer that was until now too shallow to present a significant hazard. Expect both the reactivity and the destructive potential of this layer to increase as new snow accumulates and settles. Increased loading also raises concern for a deep persistent layer that is now buried up to 200cm deep in the snowpack. Both natural and rider triggerable loose dry avalanches out of steep terrain can also be expected as new snow accumulates.

Snowpack Summary

A fresh storm slab is blanketing the region, continuing to bury a surface hoar layer that could be found up to 15cm deep in the snowpack on Thursday. Areas with this layer and where previously wind affected surfaces exist will be more reactive as the new load increases. Watch for shallow wind affected areas that will not gain strength as quickly as deeper, well settled snowpack areas. Snow depths increased rapidly last week, bringing treeline snow depths to about 200 cm. The mid-November crust is buried anywhere from 20-200 cm depending on aspect and elevation. While this crust has been unreactive thus far, increasing load may bring it to its breaking point, especially in areas with shallow or variable snowpack depth.

Avalanche Problems

Storm Slabs

Storm slabs are growing larger and more reactive with new snow. Strong southwest winds have loaded lee slopes and terrain features.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Be alert to conditions that change with elevation.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 3

Persistent Slabs

The mid-November crust is now buried up to 200 cm deep. Storm loading may allow this layer to react where the snowpack is thin or variable. A large avalanche within the storm slab may also provide enough of a trigger to step down to this layer.
Use caution in areas where the old surface crust was polished by the winds before it was buried.Use caution on open slopes with convex rolls that may propagate long avalanche fractures.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3