Our party was on top of west bowl when we observed a helicopter land on the ridgeline between main days and banana belt. The hurricane force winds blowing snow (or maybe the helicopter was causing vibrations?) caused at least 2 avalanches. 1 large avalanche in main days (guessing 250' wide) which most likely sympathetically released 1 smaller avalanche 100' or so up the ridge (50' wide). The larger of the two appeared to be 3' deep.

There was also another, and even larger, avalanche in banana belt. Zooming in on photos the crown appeared to be up to 5' feet and who knows how wide. We did not see this slide but are assuming this ran the same time as the avalanches in main days as there are fresh looking chunks of snow that did not run far.

[Forecaster Comment - Thank you for the observation. The avalanche was initially triggered by the helicopter landing at the top of Banana Belt, and that slide sympathetically released the two other avalanches in Main Days.]