Slide off Bombtram

Witnessed while driving the highway, so most information unknown other than the size and quality of the powder cloud. Initiated in ALP; powder cloud was very large and blew across highway/filled valley. The powder cloud seemed very dry, which was very different from the numerous size 1 loose-wet slides we saw later in the day, so our best guess for problem type is wind-slab or loose-dry. It's possible this was triggered by the rising sun on the south-facing part of the bowl or a sun-exposed aspect down the ridge. Location is my best guess as we were moving fast, but you can see two old bombtram towers on the ridge line for reference.