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Avalanche Forecast

Apr 20th, 2019–Apr 21st, 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
2: Moderate
The avalanche danger rating below treeline will be moderate
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
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
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Jasper.

Up to 30cm of recent heavy snow with winds has activated the problems with continuing natural activity. Give the new snow a couple of days to settle and bond.

Weather Forecast

The next couple of days will be generally sun and cloud, no new snow except for maybe a little on Monday and Tuesday, and rising incrementally freezing levels. A wind event may arrive Monday evening with 70km/hr winds.

Snowpack Summary

Moderate winds, mild temperatures and 30cm of new heavy snow Thursday night created widespread slabs in the alpine and into tree line. It rained at lower elevations making isothermal conditions where enough snow exists. A persistent facet weak layer down 40-70cm exists in some locations.

Avalanche Summary

Saturday's field patrol observed loose wet up to size 2, persistent slabs to size 3 on mainly NE aspects in alpine, and also thin windslabs size 2-2.5 E aspects. Yesterday there was a natural cycle with the recent 30cm storm. Friday's avalanche control on Highway 93 produced several wind slab avalanches up to size 2 and some stepped down.

Confidence

Avalanche Problems

Wind Slabs

Up to 30cm of new heavy snow has built reactive slabs. They vary in depth from 20cm to up 60cm thick depending on loading patterns.

  • Use caution in lee areas in the alpine and treeline. Recent storm snow has formed wind slabs.
  • The new snow will require several days to settle and stabilize.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5

Persistent Slabs

The new snow load initiated a natural cycle on this problem the past couple of days. Give it a few days to settle. Consequences would be severe if initiated.

  • If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Loose Wet

Activity increases with afternoon warming and less of an overnight freeze. Caution around terrain traps where small slides would have severe consequences.

  • Use extra caution on solar slopes or if the snow is moist or wet.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: All aspects.

Elevations: Below Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2.5