Cornice Drop initiating slab avalanche E Aspect

At exactly 12 o'clock noon I witnessed a cornice drop from an east aspect initiate a slab avalanche that slid 300 feet vertical, 1-1.5' crown, 125 ft at widest part of the slab. The slope that the cornice dropped onto was an unsupported slope above shallow cliffband and looked to be wind loaded with fresher snow from last weeks small storms. Debris did not look to be too deep, but enough to partially bury someone, it did not run far enough to deposit in lower terrain trap features.There was intense solar today and things were getting quite warm around 11:00 AM. South aspects at 1215 were close to unsupportable below 8500'.