Avalanche Forecast

A ridge of high pressure brings very warm and sunny conditions which are expected to persist until the end of Sunday. 

Thursday night: Clear, light to moderate N wind , freezing levels 2000-2500 m.

Friday: Sunny, light N wind, freezing levels around 2700 m with an inversion. 

Saturday: Sunny, light variable wind, freezing levels near 3000 m with an inversion.

Sunday: A mix of sun and cloud, light to moderate SW wind, freezing levels around 2700 m with an inversion. 

On Wednesday, some small natural and skier-triggered loose wet avalanches were observed from steep terrain features on all aspects. An isolated natural cornice failure was also reported. 

On Sunday, a near miss occurred on the late-January persistent weak layer in the area of Spectrum Peak, near Rainbow Mountain. At least three large avalanches with 1-2 metre crown fractures were remotely triggered by a group of hikers but no one was caught. Wind loading in the start zone may account for fracture depths that exceed the typical burial depth of the suspected weak layer.

On Saturday in the South Coast Inland region, a fatal size 3 (very large) skier-triggered avalanche was reported in the Duffey Lake area which also failed on the late-January weak layer. This avalanche was triggered in a upper treeline feature on a northeast aspect and showed significant propagation. Click here to read a more detailed report. 

This is the same layer that was responsible for a skier triggered size 2.5 avalanche last week on Rainbow mountain. Several smaller skier triggered avalanches on this layer were also reported last week. Most of the avalanche activity on this layer has taken place between 1800 m and 2000 m but it can also be found above and below this elevation band.

Warming temperatures and recent light rain has moistened the surface on all aspects and elevations. Formation of surface crust began Wednesday night and is expected to continue Thursday night with clear skies in the forecast. Prior to the warming and rain, strong winds had caused extensive wind effect and wind slab formation in exposed terrain at higher elevations. 

The problematic January crust/facet interface is now buried down 30 to 70 cm. This layer is most prominent between 1800 m and 2000 m, but may be found just above or below this elevation band. It had produced several human and remote triggered avalanches last weekend. Although this layer is widespread, its exact composition and reactivity has significant spatial variability. In sheltered terrain at treeline and just above, surface hoar may sit on the crust which has the potential to further increase the reactivity of this interface. 

• Be aware of the potential for large avalanches due to the presence of buried weak layers.
• Remote triggering is a concern, watch out for adjacent and overhead slopes.
• Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
• Extra caution is needed around cornices under the current conditions.
• Avoid exposure to steep, sun exposed slopes, especially when the solar radiation is strong.