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Avalanche Forecast

Nov 26th, 2017–Nov 27th, 2017
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
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
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

Regions: South Rockies.

Few observations and little information means lots of uncertainty in the forecast. Be cautious in lee areas where wind slabs have formed. If triggered these slabs may have the potential to step-down to a deeper layer.

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

Flurries with up to 10-15 cm of snow and strong west winds are forecasted for Sunday night.Monday: Mix of sun and cloud. Moderate to strong west wind. Alpine temperature -8. Freezing level 1100m.Tuesday: Flurries. Accumulation 5-10 cm. Moderate to strong west wind. Alpine temperature -5. Freezing level 1200m.Wednesday: Mix of sun and cloud. Moderate to strong west wind. Alpine temperature -10. Freezing level 1100m.

Avalanche Summary

There is very little information or observes in the region at this time. To the north, Kananaskis Country reported natural, persistent slab activity to Size 2.5 initiating on a east aspect at 2700m in the alpine and running to treeline, damaging trees on Saturday. While natural avalanche activity is likely to taper off with a return to cooler temperatures and lowering freezing levels, the possibility of triggering a deeper layer in the snowpack still exists.

Snowpack Summary

Last week saw rain drench the snowpack from valley bottom to mountain top, followed by 10-15 cm of snow at higher elevations. Warm temperatures and high freezing levels again on Sunday are suspected to have brought light rain up to 2400m and light snow above. Snowpack depths across the region are suspected to vary from 40-60 cm at 1800m elevation to 80-100 cm near 2300m. Several crusts are expected to exist within the snowpack including the most recent rain crust which is now buried by 10-15 cm of moist snow. Below this crust lies the Halloween crust as well as the early October rain crust at the base of the snowpack, and the snowpack is believed to be moist to ground.

Avalanche Problems

Wind Slabs

Watch for wind slabs from redistributed storm snow on north to south slopes at higher elevations.
Use caution in lee areas. New snow and wind loading may have created wind slabs.If triggered, wind slabs may step down to deeper layers including persistent slabs (see above).

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

There are several crusts now buried within the snowpack. As temperatures cool off these deeper layers may become less of a concern until then, assume that anything triggered near the surface may have the potential to step-down to a deeper layer.
Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Start with lower angle slopes before gradually working up to steeper objectives.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3