Avalog Join
Archived

Avalanche Forecast

Feb 17th, 2017–Feb 18th, 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
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
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.

Strong winds have contributed to a touchy storm slab problem at alpine elevations. Be sure to shift to a more conservative mindset as you transition to alpine terrain.

Confidence

Moderate -

Weather Forecast

Saturday: Mainly cloudy with scattered flurries and a trace to 5 cm of new snow. Winds light from the south. Freezing level to 1000 metres and alpine temperatures of -4.Sunday: Mainly cloudy with isolated flurries and a trace of new snow. Winds light to moderate from the southeast. Freezing level to 1000 metres and alpine temperatures of -5.Monday: Flurries bringing 10-15 cm of new snow. Winds light to moderate from the south. Freezing level to 1000 metres with alpine temperatures around -3.

Avalanche Summary

Two Size 2 storm slabs were successfully targeted with explosives in the Whistler area on Thursday. Both featured 60 cm crown fractures. Evidence of several recent wet slab avalanches having run to Size 2 was also observed on Thursday, while loose wet avalanches ran to Size 1.5 below 1900 metres. These slides were triggered naturally during the recent warming event. Reports from Wednesday included numerous storm slabs releasing naturally as well as with explosives and ski cutting to Size 2 in the Whistler area. Ski cut Size 1 slabs were noted running slowly over long distances.

Snowpack Summary

Up to 40cm of new snow has been affected by strong southerly winds to form reactive storm slabs over hard, wind-affected snow (and crust on solar aspects) above about 1900 metres. These storm slabs form our primary avalanche hazard. Below this elevation, heavy rain saturated our lower treeline and below treeline elevations, leaving refrozen crust on the surface between 1900 to about 1500 metres and moist snow at the surface below that elevation. The mid and lower snowpack are generally well settled and strong. However, there remain a number of facet and crust layers (down 60-80cm in shallower areas) that are currently dormant but will require monitoring, especially in shallow, rocky areas.

Avalanche Problems

Storm Slabs

Fresh storm slabs exist mainly at alpine elevations, becoming thinner where precipitation fell as rain. Maintain awareness of new snow depth as you gain elevation and expect the potential for human triggering the full depth of new snow.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.Use caution in lee areas in the alpine and treeline. Recent storm snow has formed touchy slabs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2