The Missoula Avalanche Center released on Tuesday its initial findings on the February 28 urban avalanche that buried four people, killing one.
According to the report, a snowboarder triggered a hard slab avalanche 658-feet wide on a west facing, 35 degree slope of Mount Jumbo at 4:15 on that Friday afternoon.
The snowboarder was caught by the avalanche but stopped himself by using his snowboard, and the snowboarder held on to the bed surface as the snow passed by.
The avalanche slid 2,200-feet down Mount Jumbo, gathering additional snow and gaining speed. The average depth of the slide was 2.5-feet, or 4-feet at it's deepest points.
The Missoula Avalanche Center has not yet interviewed the snowboarder, and a complete report will be posted once the Missoula Police Department completes its investigation.
To view the preliminary report, click here.