Avalanche Forecast

A serious avalanche incident occurred in the backcountry just east of Revelstoke on Wednesday. Details are available here. This is representative of the recent storm snow above a crust problem.

Otherwise, reports from Monday and Tuesday included many more storm slab and wind slab avalanches, several that were noted for being triggered remotely (from a distance) and a significant number of avalanches attributed to the problematic late-March and early April failure planes discussed in our snowpack summary, now buried under the full depth of recent snowfall. The presence of surface hoar and facets in particular has been noted in some of the more prominent reports of touchy conditions from the past few days.

Looking forward, the need for backcountry travelers to manage a wide range of avalanche concerns that vary by elevation and aspect continues.

Recent storm snow totals at higher elevations (where it is wintery and the snow is dry) are around 30-60 cm, with up to 100 cm reported at high elevations on the west side of the Purcells (e.g. near the Bugaboo group). And of course it's deeper on lee features

All this snow overlies either a widespread melt-freeze crust buried April 7, a weak interface of faceted snow and surface hoar buried at the end of March, or some combination of the two. As the recent snow strengthens, both of these interfaces can serve as weak layers; numerous recent avalanches, some with wide propagation, are attributed to each.

The mid-snowpack is strong. However, November depth hoar is still prominent at the base of the snowpack. This layer remains a concern in rocky, shallow, variable depth snowpack areas at treeline and above.

Thursday Night

Mix of cloud and clear periods. Light west or southwest winds. Treeline temperatures around -8 with freezing levels to valley bottom.

Friday

Sunny with cloudy periods. Dry. Light west winds. Treeline high temperatures around 0 C with freezing levels to around 1600 m.

Saturday

Increasing cloud with isolated flurries. Light to moderate south winds increasing over the day and evening. Treeline high temperatures around +2 C with freezing levels to 2000 m.

Sunday

Cloudy with trace to 5 cm of snow. South light winds and moderate gusts. Freezing level near 2000 m and treeline temperatures around zero.

More details can be found in the Mountain Weather Forecast.

• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
• Stay in tune with the physical environment, conditions may change throughout the day.
• If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
• Minimize exposure to sun-exposed slopes when the solar radiation is strong.
• In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.