Warm temps and rain caused three separate avalanches at the Dugway on Hwy 89 in Logan Canyon on Tuesday. The first occurred around 12:30pm and was called in by a maintenance worker. It covered both lanes with 3-5' of debris. The highway was immediately closed and northbound traffic was turned around while remaining southbound vehicles were ushered through once the plow cleared a single lane. The avalanche was a wet, loose avalanche likely triggered by a sudden spike in rain intensity as the rain/snow line ascended in elevation. The snowpack in that path was roughly 70-90 cm so the rain percolated through to the ground quickly. The avalanche ran only about 150' vertical.
A second avalanche just to the south of the first occurred at approximately 1pm and also covered both lanes of the highway though not as deeply, 1-3 feet. It too only ran about 150' vertical. One remaining public vehicle was able to drive through the deposition of the second though only with 4wd. It was decided then to not allow UDOT workers into the area to clear due to the continuing danger.
A third avalanche hit the road at about 1:30pm landing in between the first two. This one ran about 300' vertical with a much higher starting point in the path. It appears to have been triggered by strong winds and subsequent roller balls. It widened out to about 40' and entrained more snow on the way down. It too covered both lanes of the highway. (see video below of third - poor quality)
No other significant avalanche activity was noted in the canyon during that time though there were signs of instability like roller balls everywhere. A few smaller avalanches occurred over night of the 7th-8th at the Dugway but only affected the inner lane of the road. UDOT crews revisited the site the morning of the 8th and began a clean up effort.
Logan Canyon remained closed until 11am Wednesday Feb 8.