Avalanche Forecast

Issued: Jan 3rd, 2017 3:00PM

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

Alberta Parks matt.mueller, Alberta Parks

The cold has returned. Hopefully Tuesday was the coldest, but time will tell. So far the cold hasn't impacted the snowpack, but if it continues, expect some surface facetting.

Summary

Confidence

High -

Weather Forecast

Forecast for Burstall Pass:Minus 23° overnight tonight. A mix of sun and cloud tomorrow with no precipitation expected. Day time high of -14°. Northerly winds at 20-30km/hr in the alpine.

Avalanche Summary

Nothing new.

Snowpack Summary

Nothing new for snow in the last 24 hours. No surprise given the arrival of more cold arctic air. Last night saw lows of -36 on the Spray Rd. So far this cold has done little to change the overall snowpack character. The surface windslabs appear at treeline elevations and extend up to the high alpine on N-S aspects. The treeline midpack is continuing to lose strength and has a distinctly hollow, or "upside down" feel to it. The Dec 18 facets are still the main concern and are down approximately 40-50cm at treeline. The "deep" persistent layer (named for it's relative depth within the snowpack-in the bottom third) is next on the list of concerns. This is down 80-100cm at treeline and is starting to show signs of weakness in stability tests. Both of these layers are widespread in terms of aspect.The high alpine did see some wind transport today from the north. Its doubtful these formed any significant slabs given the cold, but there could be some isolated slabs in immediate lees on SE-SW aspects.

Problems

Persistent Slabs

An icon showing Persistent Slabs
This persistent slab is dense and is sitting on top of a 10cm weak facet layer(Dec 18th). If this layer fails, it has the potential to entrain large amounts of snow and/or trigger the deeper November crust.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Choose well supported terrain without convexities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Triggering is more likely in shallow snowpack areas and rocky features.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

An icon showing Wind Slabs
Mostly 10cm thick slabs in open areas at all elevations.
Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 4th, 2017 2:00PM

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