Several large whumpfs on way to Fawn Pass, YNP

We skinned out from Fawn Pass trailhead into the Fan Creek drainage, and eventually headed up and across a small ridge. We experienced several large whumps, specifically on flat ground in lightly treed areas, some of which resonated out roughly a few hundred yards, and shook snow off of small trees. Had a few isolated but large/loud collapses on ~20 degree slopes as well. No cracking or propagation followed that we could see. No recent signs of avalanche activity in the area, and we tried to loose something from a few test slopes with no success. South aspects were becoming very crusty in the warm sunshine today.