Stay on mild terrain and avoid lee aspects and terrain features at treeline. Periodic closures on Hwy 93 in the Icefields area will take place between 1000 hrs and 1500 hrs for up to 2 hours. Please adjust your travel plans accordingly.
Weather Forecast
Forecast models have reduced the amount of precipitation that is expected on Sunday and for the remainder of the storm. However the freezing level will rise as high as 1800m through the night as the next pulse comes through. This equates to some heavy snow that will deposit around treeline. Expect steady, Strong SW winds in the alpine.
Snowpack Summary
Below 2000ms will see an infusion of rain and/or wet snow. With a highly variable snowpack in the region, expect this to overload lingering instabilities like the Dec 20 interface, down 15 to 40cm. Scoured open slopes in the alpine will likely stay scoured as these systems move through. Sheltered areas may see up to 20cm accumulation.
Avalanche Summary
A size 2.5 slab avalanche occurred today in the Parker ridge area by a skier. This happened on a NE aspect at treeline. Below treeline, there were numerous size 0.5 to 1 loose snow avalanches going to ground as a result of the overnight rainfall. Many of these locations had less than 20cm of snow on the slope.
Confidence
Intensity of incoming weather systems is uncertain on Monday
Problems
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.