Avalanche Forecast

Issued: Feb 14th, 2019 8:00AM

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

ross campbell, Parks Canada

Glacier.

The best skiing and riding conditions exist at and below tree line in sheltered locations. This is also where the January 17th Surface Hoar layer loiters.

Summary

Weather Forecast

A mild inversion will settle in at higher elevations today, accompanied by clear skies and light winds, with a high of -8 in the alpine. Clouds will start to roll in this afternoon, flurries overnight and up to 10cm of new snow for Friday. Saturday may give us another 5cm, before the Arctic High-Pressure moves back South over Rogers Pass.

Snowpack Summary

A dusting of new snow covers old hard wind slabs, and scoured surfaces in the ALP and exposed areas of TL. Cold temperatures continue to promote near surface facetting at all elevations; deteriorating the bonds of the upper snowpack. Wind slabs were most active on solar asp, where crusts are buried. The Jan 17 SH is down 50-70cm at TL and below.

Avalanche Summary

Yesterday we observed two small sz 1.5 wind slabs on north aspects in "extreme terrain", in the alpine. On Saturday there was a natural cycle triggered by strong N-NE winds. Since the weekend we have only seen sporadic small wind slabs up to size 1.5 in the alpine. There have been no reports of any new avalanches on the Jan17th PWL in over a week.

Confidence

Problems

Wind Slabs

Saturday's wind event ravaged the upper snowpack in the Alpine and exposed areas of Tree Line; leaving behind a variety of surface conditions varying from Pencil resistance hard slabs to soft near surface facetting.

Be cautious in shallow snowpack areas where triggering is more likely.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

The Jan 17 Surface Hoar layer is buried 50 to 70cm at and below tree line. This interface exists on all aspects and most reactive between 1400-1900m; especially on steep solar aspects where it overlies a crust.

Watch for whumpfing, hollow sounds, and shooting cracks.Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 15th, 2019 8:00AM