Avalanche Forecast

Moderate - Intensity of incoming weather systems is uncertain on Monday

Light snowfall is forecast for Sunday overnight. On Monday, mostly cloudy conditions are expected in the morning with sunny conditions in the afternoon. Alpine wind is expected to be light to moderate from the northwest and freezing levels are forecast to climb to around 2000 m or so by Monday afternoon. On Tuesday, sunny conditions are expected with the potential for valley fog to develop. Alpine wind is forecast to be moderate from the southwest. Freezing levels are forecast to reach as high as 3000 m and a temperature inversion will likely develop. A weak storm pulse is expected to reach the region sometime on Wednesday. Freezing levels are forecast to remain above 2500 m and high elevation rain is expected.

On Saturday, one natural size 2 storm slab was observed on a southeast aspect at 2300 m. A size 2 storm slab avalanche was remotely triggered from 60 m away on a northeast aspect at 2100 m elevation. The slab was around 50 cm thick. On Friday, numerous natural storm slab avalanches size 2-3 were observed throughout the region. On Monday, the recent storm snow is expected to remain reactive to human triggering, especially in wind affected terrain. Persistent slab avalanches are also a concern, especially in the thinner snowpack areas of the region. Extra caution is recommended during the heat of the afternoon, especially on sun exposed slopes. This will become increasingly important through the week as freezing levels remain very high. We are entering the first period of substantial warming following months of sustained cold conditions. Any weaknesses lingering in the snowpack will be tested in the coming days.

30-50 cm of storm snow has typically accumulated of the past few days and is settling quickly due to the warm temperatures. Recent strong winds from the south and west have redistributed this snow in exposed terrain forming touchy wind slabs. Weaknesses may still exist within this recent storm snow with reports of 'upside-down' conditions and easy shears within the storm snow. All this new snow is also bonding poorly to the old interface from early February that includes old hard wind slabs and crusts as well as faceted snow and surface hoar on sheltered open slopes. The persistent weakness buried mid-January is now down around a metre and consists of buried surface hoar in sheltered areas, and/or widespread faceted old snow. It has generally stabilized but may remain reactive in isolated areas where buried surface hoar is preserved. Another surface hoar/facet weakness buried mid-December can now be found over a metre in shallow snowpack areas. These old weak layers are expected to get tested with the upcoming period of sustained warming, and if they wake up, very large avalanches are possible.