Avalanche Forecast

Issued: Mar 17th, 2017 4:05PM

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

rupert wedgwood, Parks Canada

Jasper.

Warm temperatures and upwards of 30cm of storm snow is on its way. Avalanche danger will remain at a seasonal high until this passes.

Summary

Weather Forecast

Overnight at the Icefields 5 cm of snow, winds 40 km/h W. Freezing level at valley bottom. Saturday 25cm of snow mostly in the south of the region and at higher elevations. Ridge wind SW 25 km/h gusting to 75 km/h. Freezing level 2100 metres with rain in the townsite. A clearing and cooling trend starts Sunday afternoon, moderate SW winds.

Snowpack Summary

Upwards of 45cm of snow has fallen this week. SW winds are building a reactive wind slab at treeline and above. The mid-pack consists of persistent slab layers intermixed with weak facets. The base is weak facets, depth hoar, and an ice crust from November. A temperature crust exists up to 2000 m.

Avalanche Summary

Numerous large natural avalanches (class 3) were observed from the Maligne area to the icefelds at Tree Line and above. These slab avalanches are failing at varied depths; from recent storm snow to deeper older instabilities. Warm temperatures and precipitation will keep the landscape dangerously active.

Confidence

Freezing levels are uncertain

Problems

Loose Wet

Rain to treeline and warm temperatures will produce numerous avalanches of this type. Some of these will step down to ground producing full path releases.

Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.Avoid all avalanche terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 3

Wind Slabs

40cm of storm snow over the week has formed a dangerous windslab. Wide crowns up to 2m deep have been seen from Maligne to Parkers area. Strong to extreme SW winds and warm temps will keep this layer very active.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.It is a good time to stay within the boundaries of a ski resort.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Deep Persistent Slabs

The widespread observations of large and deep avalanches indicates strongly that many of these events are from this instability. Increased loading and warm temperatures will keep this layer active.

Avoid all avalanche terrain.Be careful with low angle slopes that may not normally be a concern.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 4

Valid until: Mar 18th, 2017 4:00PM