Avalanche Forecast

Issued: May 3rd, 2019 3:00PM

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Wind Slabs, Loose Dry and Loose Wet.

Alberta Parks mike.koppang, Alberta Parks

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Another 10-15cm of snow is forecast over the next 24hrs with rain at lower elevations.  Use caution as spring time snow amounts can be tricky to forecast and some areas may receive higher amounts.

Summary

Confidence

-

Weather Forecast

Forecast models differ but in general we are expecting to see up to 12cm of snow and or rain at lower elevations over the next 24hrs.  Rain will rapidly overload the weak basal layers in the snowpack and likely trigger loose wet and/or wet slab avalanches.  Pay close attention to temperature and precipitation type. Day time high are forecast to be around +4 with a freezing level close to 2200m. 

Avalanche Summary

Avalanche activity was decreased on Friday but on thursday there were numerous loose dry up to sz 1.5, along with windslabs up to sz 2.5.  Loose wet avalancehs were also observed promptly initiating after the sun came out.  Keep an eye on incoming solar radiation.

Snowpack Summary

30-45cm of snow has fallen over the past week.  This new snow has fallen under generally warm temperatures and variable NW winds.  Southern and solar aspects are kissed by the recent warm temperatures and as a result, you should expect to encounter crusts on these aspects.  Northern aspects in alpine areas are still hold dry snow.  Whats critical to evaluate is the bond of this new snow with the underlying snow surface.  Due its warm nature as it fell, so far we have observed a good bond with the underlying crust.  This can be highly variable though so we encourage backcountry users to dig down and inspect this interface.  Northern aspects have windslabs in alpine areas especially along ridgelines.  Use caution as the entrances to runs and check for these concerns before committing. 

Problems

Wind Slabs

An icon showing Wind Slabs

Recent snow and wind have created fresh surface wind slabs in Alpine terrain. Depth of slab and bond with the underlying surface are highly variable. Dig frequently while traveling to keep a good handle on this avalanche problem.

  • If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Dry

An icon showing Loose Dry

Loose dry slides will initiate following the influx of the forecast new snow on Saturday. 

  • Use extra caution on slopes if the snow is moist or wet.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.
  • If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 2

Loose Wet

An icon showing Loose Wet

If forecast precip falls as rain, watch for loose wet avalanches to begin due to the rapid loading.

  • Use extra caution on slopes if the snow is moist or wet.

Aspects: All aspects.

Elevations: Below Treeline.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: May 4th, 2019 3:00PM

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