Avalanche Forecast

Issued: Mar 14th, 2015 8:07AM

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

andrew jones, Parks Canada

Glacier.

New precipitation and warm temperatures means natural avalanches are possible and human-triggered avalanches are likely today.

Summary

Weather Forecast

A frontal system will bring strong southwest winds and precipitation to Rogers Pass today. Models suggest 10-15cm of snow could fall by this evening, but only at higher elevations. Freezing levels are already above 1900m and are expected to rise to 2000m. The system moves out of the area late tonight, beginning a period of high pressure.

Snowpack Summary

Isothermal snow in the valley bottom did not refreeze overnight and received 4mm of rain this morning. Above 1900m, 10cm of new snow fell with moderate southerly winds. Widespread and reactive wind slabs in exposed areas are now buried. Crusts in the top 30cm are weakening with continued warm temps and triggering of deeper layers is possible.

Avalanche Summary

A natural cycle of loose wet avalanches yesterday afternoon in the highway corridor. Avalanches started in moist, high alpine start zones and ended with wet deposits up to size 2.5. Wind slab avalanches were observed on the north face of Mt Cheops to size 1.5. On Dome Glacier, a size 2.0 wind slab was triggered by the 5th skier on the slope.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

Wind slabs were reactive to skiers triggers yesterday. Continued warm temperatures and a new precipitation will keep this problem primed today. Widespread wind slabs at higher elevations may now be concealed by 10cm of new snow.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Wet

A widespread loose wet natural avalanche cycle was observed yesterday afternoon. A poor overnight re-freeze combined with ongoing warm temperatures and new precipitation will continue to destabilize the upper snowpack.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Avoid avalanche terrain during periods of rain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

Deep instabilities in the snowpack have been dormant in recent weeks but may become reactive. The bridging properties of near surface crusts weaken as the snowpack warms. New snow today will make persistent slabs a key problem.

Be aware of the potential for large, deep avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Valid until: Mar 15th, 2015 8:00AM