Avalanche Forecast

Issued: Jan 14th, 2018 5:28PM

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

tim haggarty, Parks Canada

Jasper.

A cycle of small, Loose Wet Avalanches was the result of the temperature inversion, clear skies and calm winds today. The temperatures look to remain warm for the next two days at least.

Summary

Weather Forecast

Pacific air will continue to override cooler air in the valleys producing a temperature inversion through to Tuesday. Winds should remain light from the SW through Monday until late in the day Tuesday when they will increase and potentially bring some light flurries or rain.

Snowpack Summary

10-15cm of recent snow has blown into thin slabs TL and above. Old slabs, 10-40cm deeper, sit on a weak layer of facets or surface hoar TL and above. In sheltered areas the new snow sits a weak,faceted upper snowpack at all elevations. A strong mid snowpack crust is providing strength but is weakening. The lower snowpack continues to lose strength.

Avalanche Summary

A cycle of loose wet avalanches started on steep south slopes at midday and followed the sun onto West slopes into the mid afternoon. The inversion, calm winds, and strong sun all factored into these events which originated as high as 2900m and ran up to sz 2 in confined features. Only one slab was observed to be triggered by all of this activity.

Confidence

Timing or intensity of solar radiation is uncertain on Monday

Problems

Persistent Slabs

Pockets of old, buried slab are found in exposed areas. These sit on weak, faceted snow that lacks strength, and may fail, to mid-pack depths. Treat all wind exposed areas with care but approach larger, uniform features and thin areas with caution.

Avoid shallow snowpack areas where triggering is more likely.Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Loose Wet

Sunday's cycle of these will likely result in crust limiting the further potential of this problem however temperatures seem a bit uncertain and if the sun is out again, it is worth taking note.

Avoid ice climbs exposed to steep rocky terrain on solar aspects during the middle of the day.If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.

Aspects: North, North East, East.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

The recent snow was redistributed into thin, spotty slabs in exposed areas. These slabs sit on freshly buried, weak facets and surface hoar in some areas. Triggering one of these slabs may provide enough load to trigger the deeper persistent slab.

Watch for surface cracking and stiffer surface layers of snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Jan 15th, 2018 4:00PM