Avalanche Forecast

MONDAY NIGHT: Cloudy with snowfall, accumulation 10 to 20 cm, 60 km/h northwest wind, alpine temperature -6 C, freezing level 400 m.

TUESDAY: Cloudy with early-morning snowfall and afternoon clearing, accumulation 5 cm, 40 km/h northwest wind, alpine temperature -8 C.

WEDNESDAY: Increasing clouds with afternoon snowfall, accumulation 5 cm, 30 km/h west wind, alpine temperature -8 C.

THURSDAY: Cloudy with snowfall, accumulation 20 to 40 cm, 80 km/h southwest wind, alpine temperature -6 C.

Many storm slab avalanches were triggered naturally, by explosives, and by riders on Sunday. They were small to large (size 1 to 2.5) and on all aspects and at all elevations. We may say extensive evidence of avalanche activity once it clears up. A loose wet avalanche cycle was also noted below treeline from the substantial amount of rain that fell over the weekend.

Looking towards Tuesday, natural avalanche activity may taper as the snow stops falling but human-triggered avalanches will still be likely to be triggered.

Much of the region has seen over 100 cm of snow accumulation over the weekend above around 800 m with associated strong south to southwest wind. Storm and wind slab avalanches likely developed rapidly during the storm and a natural avalanche cycle likely occurred at all elevations from rapid snow and rain accumulation. Another 15 to 25 cm of snow may accumulate Monday night with strong northwest wind, continuing the avalanche cycle into Tuesday morning!

All of this snow may not bond well to previous surfaces buried mid-February, which may include:

• Weak and feathery surface hoar in sheltered areas, with the most suspect elevation bands being lower alpine, treeline, and within openings below treeline;
• A melt-freeze crust found below treeline, particularly on southerly aspects;
• A 20 to 40 cm thick layer of sugary faceted grains that developed during cold periods; and/or
• Hard wind-affected snow, particularly in exposed alpine and treeline terrain.

The mid-pack has been reported as being well-settled. There are presently no deeper concerns.

• Travel in alpine terrain is not recommended.
• Give the new snow several days to settle and stabilize before pushing into bigger terrain.
• Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.