Mcginnis creek area. Rain on the north fork and a wintry mix up to about 5500 feet. Had one section break free. Slab maybe 50 feet wide and 6" thick as I was coming back down to the road we were on. Make a left off main road and cross 2 bridges. It heads towards kimmerle basin. 20 mph winds coming over the ridges. Conditions were hard pack snow. Heavy and wet.
6" thick. Location speculated from description.