Avalanche Forecast

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

A ridge of high pressure brings dry, warm, and sunny weather.

WEDNESDAY NIGHT: Clear skies, moderate southwest wind, treeline temperatures drop to -5 C.

THURSDAY: Sunny, moderate south wind, freezing levels reach the 1900-2100 m range with treeline temperatures around 0 C.

FRIDAY: Mostly sunny with some afternoon clouds, light south wind, freezing level around 2000 m with treeline temperatures around -1 C.

SATURDAY: Cloudy with scattered flurries and 5-10 cm of new snow, light southwest wind, freezing level climbs to 1600 m with treeline temperatures around -3 C.

On Thursday the primary concern is natural avalanches on steep sun-exposed slopes. These will most likely present as wet loose avalanches, but larger wind and persistent slab avalanches are also possible. Read the latest Forecaster Blog for concerns about the warming.

Avalanche activity since the weekend has primarily been limited to small (size 1) wind slab avalanches on north and east facing slopes. There was also a remotely triggered persistent slab avalanche on Tuesday near Golden on a northwest slope at 2100 m (see MIN report). This avalanche failed on a 40 cm deep weak layer, with some whumpfing and cracking reported in nearby terrain. There have been a few other notable persistent slab avalanches in the northern Purcells over the past week including a large human-triggered avalanches in the east Quartz Creek on Saturday (see MIN report) and a few remotely triggered avalanches on Wednesday (see MIN report).

Rising freezing levels and sunshine will be melting, and potentially destabilizing, snow surfaces the next few days. Higher elevations have been impacted by recent wind from the southwest, likely leaving wind slabs lurking on shaded north and east slopes.

Persistent weak layers have been most active in the northern end of the Purcells where a buried layer of surface hoar that formed in late January is 40-80 cm deep and an older surface hoar layer is 60-120 cm deep at treeline. These layers may exist as a combination of facets and crusts at other elevations. Recent observations suggest these layers have been less problematic as you move further south.

Steep rocky areas where the snowpack is thin likely has addition weak layers near the base of the snowpack.

• Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
• Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
• Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
• Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.