Avalanche Forecast

Issued: Mar 19th, 2015 4:00PM

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

garth lemke, Parks Canada

Jasper.

Open South aspects below treeline have a challenging suncrust. Northerly aspects treeline and above has great skiing.

Summary

Weather Forecast

Friday and Saturday will bring freezing levels up to 2100m, clouds, and mixed rain or snow with little accumulation. Saturday night may bring 5-10cm snow or rain. Sunday may be sunny with warm temperatures as a result of solar radiation.

Snowpack Summary

Crusts exist up to 2200m on all aspects and extend higher on solar aspects. Above treeline wind slabs up to 65cm thick can be found in isolated locations. Bonding is generally good, however a graupel layer has recently been shown to shear with moderate force at the interface. Deeper weaknesses can be found near the base of the snowpack.

Avalanche Summary

No recent activity observed. A large cornice failure onto a easterly facing alpine start zone, known to be a frequent performer, failed to produce an avalanche. Limited older (>72hrs) size 2 activity from treeline and above is thought to have been triggered by solar radiation. Today's observations were limited due to poor visibility.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Saturday

Problems

Wind Slabs

Soft slab conditions on lee alpine aspects appear to have bonded well in most locations. At 2400m a graupel layer marks the interface and may be below 65cm of wind blown snow from last week. This sheared with moderate force during field tests (18th)

Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Deep Persistent Slabs

Large cornices or surface avalanches are the likely trigger.

If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Extra caution needed around cornices with current conditions.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 20th, 2015 4:00PM