Avalanche Forecast

Low - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack. Uncertainty is due to the limited number of field observations.

Unsettled conditions are expected for Tuesday as the storm system exits the region and a ridge of high pressure begins to build in its wake. 

Monday Night: Snowfall 5-15 cm, strong SW wind, freezing level low around 1000 m. 

Tuesday: Mainly cloudy with lingering flurries in the morning and sunny breaks in the afternoon, moderate to strong W wind, freezing level high around 1400 m.

Wednesday: Mainly sunny, light to moderate SW wind, freezing level high around 1800 m.

Thursday: A mix of sun and cloud, light to moderate SW wind, freezing level high around 2500 m.

On Sunday, ski cutting in the north of the region triggered several storm slabs on north and east aspects at 2000-2100 m elevation which were typically 30 cm thick and sliding on a melt-freeze crust. Visibility was limited but natural avalanches up to size 2 were also suspected. This MIN report describes triggering a couple small storm slabs and observations of shooting cracks. In the Coquihalla, a few small natural glide slab avalanches were reported from the smooth rock slab features as well as a few small wet loose avalanches from steep slopes. 

On Saturday in the north of the region, a skier triggered a size 1 wind slab on a northeast aspect at 2450 m which had an average thickness of 25 cm and slid on a melt-freeze crust. In the Coquihalla area, this MIN report and this MIN report describe small skier-triggered soft slab avalanches which were 5-20 cm thick. This MIN report describes wind loading and shooting cracks in the recent 10-15 cm of storm snow. 

As of Monday afternoon, recent storm snow totals are estimated to be 30-60 cm. This storm snow has buried a strong, supportive crust which extends to mountain top on solar aspects and to around 2200 m on northerly aspects. Strong southwest wind has redistributed the new storm snow in exposed, high elevation terrain forming touchy wind slabs and developing large cornices. 

The rest of the upper snowpack consists of a number of crust/facet/surface hoar interfaces buried in March that seem to have bonded well during the recent warm weather. 

The middle and lower snowpack are generally strong and well bonded. 

• Continue to make conservative terrain choices while the storm snow settles and stabilizes.
• Be aware of the potential for large avalanches due to the presence of a buried crust.
• Pay attention to cornices and give them a wide berth when traveling on or below ridges.
• Cornices become weak with daytime heating or solar exposure.