Avalanche Forecast

Issued: Apr 22nd, 2018 6:15PM

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

jasper snow safety, Parks Canada

Jasper.

Solar triggered avalanches and cornice failures are likely to increase in frequency the next few days as each day will be warmer than the previous days.

Summary

Weather Forecast

Monday will be sun and cloud, no new snow, high of 0 C, light SW winds, and 2300m freezing level. Tuesday will be similar, but with 2500m freezing level. Wednesday will be similar but much warmer with 3500m freezing level.Â

Snowpack Summary

Windslabs are up to 40cm deep. Sun or temperature crusts extend to treeline and continued into the alpine on southerly slopes. Persistent slabs can be found on most aspects at treeline and above. These have been most reactive to large triggers like cornice failures. Below 1,900m the snowpack is going isothermal on a daily basis.

Avalanche Summary

Sunday thereÂ was a report of a size 2 slab avalanche on the NE slopes of Lectern, initiating in the alpine and running in to treeline. Also a couple of size 2-3 moist loose avalanches observed in the Icefield's area starting in steep solar affected alpine gullies and running far.

Confidence

Timing or intensity of solar radiation is uncertain on Monday

Problems

Loose Wet

Pay close attention to the effect of solar radiation and daytime warming. Point release from rocks and cliff terrain can trigger isothermal snow below. This will be of most concern in the late afternoon.

Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Triggering this slab have been most reactive to large triggers such as a cornice failures.

Avoid shallow snowpack areas where triggering is more likely.Pay attention to overhead hazards like cornices which could trigger slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

SW winds Saturday have added to the existing wind slab and cornice problem. Although mostly thin, some wind slabs are up to 40cm thick in alpine terrain. Once initiated the potential to trigger deeper weaknesses exists resulting in larger avalanches.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Stay well to the windward side of corniced ridges.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Apr 23rd, 2018 4:00PM