A widespread storm slab avalanche cycle occured on Wednesday February 13, 2019. Most of the activity occurred at elevations below 5500 feet, but several avalanches ran at higher elevations as well. BNSF Avalanche Safety observed multiple slides and had reports of several avalanches reaching the rail grade and US Hwy 2. By the evening of the 13th temperatures were dropping and avalache activity had diminished. February 14th dawned clear and cold with excellent visibility. The sunshine started a few small loose snow avalanches but no new slab activity occured on the 14th. Observed one larger avalanche from Hwy 2 on the east face of Snowslip Mountain early morning of the 14th (photo). This slide may have stepped down to an older, buried persistent weak layer - Jan 17 crust/buried surface hoar perhaps?
Infinity Path: Ran sometime during the storm and no crown was visible. Debris ran 3/4 path terminating above the rail grade
Umbrella Fence Path: Very small amount of reached the rail.
Burnout Path: Most debris stopped above the rail on the retaining wall.
Shed 4D/Burnout Cutbank Path: Ran wall to wall early afternoon on the 12th. Debris on the rail was approximately 6-8 feet deep and 150 feet wide.
Path 1163 Headwall: Debris ran 2/3rds path terminating above the rail.
Grizzly (Gulch) Path: Observed from helicopter on 2/14 but ran sometime on 2/13. Obvious cornice fall trigger.
Observed from helicopter on 2/14 but ran on 2/13. Obvious cornice fall trigger. Debris stopped on bench about 500 vertical feet below.
Observed from Hwy 2 early morning on 2/14. Not sure, but this avalanche may have stepped down to an older buried persistent weak layer, Jan 17 crust? Size dimensions are very rough estimates.
