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Avalanche Forecast

Apr 18th, 2019–Apr 19th, 2019
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
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
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Jasper.

ROAD CLOSURE: The Icefields Parkway (93N) is closed from Parker Ridge to Saskatchewan Crossing Thursday at 2pm due to avalanche hazard with the incoming storm. For updates check: https://511.alberta.ca

Weather Forecast

Tonight will be periods of wet snow mixed with rain, 16 cm of snow, Low 0 C, wind southwest 15 km/h gusting to 45 km/h, and freezing level 2200 metres. Friday will be flurries, 9 cm of snow, 1 C, wind west 15 km/h gusting to 45 km/h, and freezing level 2300 metres. Saturday will be sun and cloud, no snow, Low -8 C, High -3 C, and West winds.

Snowpack Summary

Strong winds are moving the 5-10cm of settled surface snow about the landscape and more snow is expected. This will rest on a variety of crusts. Above 2200m on northerly slopes, a winter like snowpack can be found, with windslabs, a persistent weak layer down 20-50cm, and a facetted mid and lower snowpack which is weak in shallow areas.

Avalanche Summary

There was natural windslab activity observed in the past couple of days. The mid march PWL continues to produce whumphing in shallower snowpack areas and on moraine features, indicating unstable snow below. Thursday's patrol only had glimpses into the alpine due to strong winds and incoming storm, nothing new was noted.

Confidence

Intensity of incoming weather systems is uncertain on Friday

Avalanche Problems

Wind Slabs

Windslabs are forming treeline and above with strong SW winds and new snow arriving Thursday night into Friday.

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • The new snow will require several days to settle and stabilize.

Aspects: North, North East, East, North West.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 2.5

Persistent Slabs

Snowpack tests and whumphing would suggest that a weak layer of facets persists down 20-50cm in some areas. This layer will likely become reactive with loading from incoming snow on Friday. Use caution specifically in shallow alpine features.

  • Avoid shallow snowpack areas where triggering is more likely.
  • Whumpfing is direct evidence of a buried instability.

Aspects: North, North East, East, North West.

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 3