Avalanche Forecast

Issued: Mar 15th, 2021 4:19PM

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

timothy johnson,

Jasper.

Watch out for rising temperatures and solar heating which can increase the avalanche danger. Start early and finish early.

Summary

Weather Forecast

Tuesday: Sunny with cloudy periods. Precipitation: Nil. Alpine temperature: High -3 C. Light ridge wind. Freezing level: 1900m.

Wednesday: A mix of sun and cloud. Precipitation: Nil. Alpine temperature: Low -8 C, High -4 C. Ridge wind southwest: 10-25 km/h. Freezing level: 1800m.

Snowpack Summary

Sunny skies and warm temperatures have created crusts and moist snow on all aspects at tree line and below and into the alpine on solar aspects. There is widespread wind scouring to rock in exposed alpine features. The middle of the snowpack is supportive in deep areas but weak in shallow spots.

Avalanche Summary

Several natural wet avalanches occurred in the region on Sunday and Monday. A notable large slab avalanche occurred on a southerly aspect high on Mt. Wilson. Natural and explosive triggered avalanches stepping down to the February persistent weak layer (down 60cm) resulted in two size 2 avalanches at Marmot Basin.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Loose Wet

Watch out for solar heating and daytime warming to trigger avalanches especially from steep rocky terrain.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: South, South West, West.

Elevations: Treeline, Below Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 1.5

Persistent Slabs

Weak facets buried on Feb 20th. It is prudent to keep this on your radar with warmer temperatures as reactivity may increase. Cornices will have the potential to fail and trigger slabs below.

Pay attention to overhead hazards like cornices which could trigger slabs.
If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Deep Persistent Slabs

Caution in thin facetted snowpack areas where triggering is more likely. This is a low probability but high consequence problem.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Mar 16th, 2021 4:00PM