Avalanche Forecast

Issued: Mar 13th, 2017 4:00PM

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

Parks Canada garth lemke, Parks Canada

Weather models are not agreeing to the timing whether Wednesday's or Thursday  will have rising freezing levels and significant rain in valley bottom. Expect  danger to increase if with possibly 20mm of precipitation.   

Summary

Weather Forecast

Tuesday will be steady 20-40km/hr SW winds, clouds, flurries, and freezing level 2100m. Winds will slightly increase speed on Wednesday plus there may be very warm temperatures, significant snow at high elevations, and rain low down Wednesday afternoon into Thursday. The models are not agreeing so allot of uncertainty on outcomes.

Snowpack Summary

Steady moderate Southwest winds transporting and pressing recent 20-40cm of snow into a slab in open areas at TL and above. Generally its bonding to the old snow interface in most areas. The mid-pack consists of persistent slab layers intermixed with weak facets. The base is weak facets, depth hoar, and an ice crust from November.

Avalanche Summary

Monday's patrol observed several wet loose size 1's running in the storm snow at treeline in the Big Bend area. They were likely triggered by solar radiation.  March 11 skiers reported remotely triggering from 300m away into the alpine two size 2.5's 1.5m thick and 35m wide. They ran to bottom of the path.

Confidence

Freezing levels are uncertain

Problems

Loose Wet

An icon showing Loose Wet
Expect an increase in loose wet surface avalanches particularly when the sun comes out, temperatures remain warm, or rain occurs. Rising freezing levels will increase this danger at all elevations. Use caution around terrain traps.
Be very cautious with gully features.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs
SW winds creating slabs on lee and pressing snow on windward aspects. May be overtop decomposed SH layer on CR 30cm down on South TL aspects.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Natural activity has subsided but don't let your guard down. It remains a major concern with a extremely weak base of depth hoar. Trigger spots would be shallow zones or a step down effect if upper layers are initiated.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Mar 14th, 2017 4:00PM

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