Climbing freezing levels and rainfall are driving HIGH avalanche danger. Steer clear of avalanche terrain until the storm passes and conditions stabilize.
SW winds and additional precipitation will continue to build slabs, especially in the more predictable leeward and cross-loaded areas at treeline and above.
A 40–90 cm slab sits atop mid-pack facets and depth hoar at the ground. Expect avalanches to fail on both layers with wide propagations. The incoming weather payload is prompting another avalanche cycle. This problem will create ongoing uncertainty until the bitter end of the season.
Lake Louise patrol reported numerous size 1's triggered by explosives. Sunshine patrol reported knocking out a size 2.5 on a reloaded bed surface which reacted like a deep slab, down to rocks. A field team member near Simpson Pass reported hearing a large audible avalanche.
15-20 cm of heavy moist snow (up to 2400m) has been blown into windslabs up to 40 cm deep in leeward areas. This adds to the dense slab, 50-100 cm thick, overlying weak facets in the mid to lower snowpack and is responsible for the recent large avalanches. This condition has been most sensitive in the Bow Summit area, but expect the likelihood of avalanches to increase at all elevations with the warming.
Freezing levels are on the rise, with moderate precipitation expected to bring another 10 cm of snow by Wednesday morning. Rain is likely at lower elevations. Winds will be variable and somewhat unpredictable, potentially reaching strong speeds from the southwest. Taken together, these factors point toward an avalanche cycle.
