This probably has nothing to do with backcountry avalanche conditions, but it's just the avalanche geek in me speaking here. I couldn't help to notice that about half the roofs of the houses and condos along the Alta bypass road had avalanched with fresh slides. I must have seen perhaps 20-30 separate avalanches. I'm not sure if I've ever seen that much roof-a-lanche activity after a 1 foot snowstorm without heating by the sun. These occurred on all aspects (I included 4 photos, one from each aspect) so the sun early today probably did not have much effect, especially with the very cold temperatures and mostly cloudy skies. The avalanche in the first photo, I was able to measure the slope steepness at an incredible 23 degrees. I was also able to walk up to the edge of that avalanche and look at the snow structure. I found 1 inch thick, frozen ice crust directly on top of the metal roof and then a foot of low density new snow on top.

I'm speculating that since the storm came in warm and wet, the ice crust formed early and when the cold air arrived, the new snow piled up on top, and the ice crust then froze solid with the very cold temperatures. I'm guessing that most of these slides were glide avalanches, which you would expect, but I was most interested to see that many of them had released very recently, definitely during the day today during the very cold temperatures. The ice crust I examined was well frozen so there did not appear to be any melt water lubrication going on. Almost all of them occurred on metal roofs.

Has anyone else seen this much activity in non-wet avalanche conditions?