A close call occurred on Rainbow Mountain on Monday when an avalanche on a persistent weak layer resulted in a full burial. Remain conservative in your terrain choices to account for significant variability from one slope to another.
Winds have shifted from southwesterly to northerly. Watch for reverse-loading on south-facing slopes in areas where winds are sufficiently strong to move snow around.
A couple problematic layers may be found around 50 to 120 cm deep, including weak layers of surface hoar and faceted grains above a hard melt-freeze crust. There remains potential for storm slab avalanches to step down to these layers, resulting in large and destructive avalanches.
Monday night: Dry with clear skies. Cooling temperatures.
Tuesday: 5-10 cm new snow. Freezing level around 600 m. Winds light to moderate southwesterly.
Wednesday: 15-20 cm new snow. Freezing level around 800 m. Winds moderate southerly.
Thursday: Flurries. Freezing level around 900 m. Winds light southwesterly.
A large (size 2.5) avalanche was triggered on Monday by a snowmobiler on Rainbow mountain in alpine terrain, which resulted in a full burial and, thankfully, a successful rescue. The avalanche failed on a layer 60 cm deep. At this time the nature of the failure plane is unknown, but it is reasonable to assume it failed on one of the two weak layers discussed in the snowpack section. This avalanche points to the ongoing potential to trigger persistent weak layers in the snowpack.
A small (size 1) avalanche was also triggered on Monday by skiers on a north aspect in the Whistler backcountry, most likely in recent storm snow.
15-30 cm of recent snow has been redistributed by strong south to east winds, depositing deep pockets of storm slab into lee terrain features.
Two potential concerning weak layers may be present in the snowpack:
To date we have mostly seen sporadic avalanche activity on these layers, but they remain possible to trigger where they exist in the mountains.
The remainder of the snowpack is well-settled.
