Avalanche Forecast

A warm front will bring rising temperatures and wind on Sunday, with the bulk of precipitation forecast to fall on Monday.

SATURDAY NIGHT: Mostly cloudy, up to 5 cm of new snow, westerly wind increasing to moderate, freezing level valley bottom.

SUNDAY: Flurries up to 5 cm becoming wetter as freezing levels rise to 1500 m. Moderate west wind at treeline with strong to extreme west wind in the alpine.

MONDAY: 5 to 10 cm of snow at upper elevations with rain in the valleys, freezing level holding at 1500 m. Moderate southwest wind at treeline with strong west to extreme west wind in the alpine.

TUESDAY: Mix of sun and cloud, wind easing and switching northwest, freezing level 1000 m.

There have been a few reports of small natural wind slabs and loose dry avalanches running in the facets this week. Cornices remain large and fragile but there have been no reports of cornice falls since last weekend.

Earlier in February, there were a few reports of large avalanches (size 2.5-3) on southeast aspects in the alpine, likely releasing on a layer of facets on a crust (see a photo here), and a large human-triggered avalanche (size 2.5) on surface hoar near Quartz Creek.

Winds have varied in strength and direction over the past week, loading cornices and forming shallow wind slabs in complicated cross-loading and reverse-loading patterns at upper elevations. These wind slabs may overlie weak, sugary, faceted snow, meaning that they could break wider than expected and will likely be slow to bond. 

In wind-sheltered areas, the upper snowpack is becoming soft and faceted with the cold temperatures and the riding looks pretty good. A weak layer that formed in late January is now 30-60 cm deep. In the northern Purcells this layer has been reported as a surface hoar layer at treeline and below treeline elevations, but a combination of facets on crusts could exist at all elevations throughout the region. 

The northern Purcells also have an older surface hoar layer that can still be found 60-100 cm deep at treeline. Additional weak layers may exist near the bottom of the snowpack and steep rocky areas with a shallow or thin to thick snowpack should be considered suspect trigger points.

• Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
• Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.