Afternoon wake up call

Several downhill sled laps on adjacent slope prior to triggering, no signs of instability throughout day as we sled cut several slopes. Rider dropped into line in a slightly steeper entrance than previous laps and accidentally triggered storm slab layer as it propagated between two trees located on the run. Sledder went for a small ride but rode out. Could not get close to crown to assess weak layer due to hangfire but suspect storm interface as it was south facing and there was not alot of other evidence of windloading in this area on this aspect.