Avalanche Forecast
Regions: South Coast Inland.
The recent storm snow is expected to be touchy on Tuesday and human-triggered avalanches are likely.
Depending on the timing and amount of sun, solar-triggered avalanches are also possible. Extra caution is recommended around steep, sun-exposed slopes.
Confidence
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.
Weather Forecast
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.Â
Monday Night: Snowfall 5-15 cm, strong SW wind, freezing level low around 1000 m.Â
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.
Avalanche Summary
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.Â
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.Â
Snowpack Summary
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.Â
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.Â
The middle and lower snowpack are generally strong and well bonded.Â
Terrain and Travel
- 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.
Avalanche Problems
Storm Slabs
The recent storm snow is expected to be touchy on Tuesday, especially in wind exposed terrain.
If the sun is out for extended periods, solar-triggered storm slabs are likely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2.5
Cornices
Cornices have grown large during the recent storm and may be fragile on Tuesday, especially with extended exposure to the sun. Falling cornices are a likely trigger for slab avalanches on the slopes below.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5
Loose Wet
Loose wet avalanches should be expected from steep, sun-exposed slopes during the heat of the afternoon if the sun is out for extended periods.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 2