Remote skier triggered avalanche near Negro Canyon

On North aspects in the Negro Canyon zone today, widespread evidence of instabilities were observed. Leading up to this slide, we observed whumphing and lots of shooting cracks, some of which were 50+ feet long. Closer examination showed that most of these instabilities originated on the Jan 9th buried surface hoar layer. This layer ranged from very shallow to over a meter deep, depending on terrain and wind loading. This persistant slab was triggered from the skin track, on low angle terrain (less than 25 degrees), over 100 feet away from the start zone. A large whumph preceeded the slide, and the crown failure propagated far ( over 400 feet), and pulled back onto terrain less than 30 degrees, wrapping around this rollover feature for quite a ways. The failure layer was the Jan 9th buried surface hoar, and the bed surface was glistening with large surface hoar  (1CM+). Significant shooting cracks were also observed in the vicinity, for hundreds of feet surounding the slide. There was no step down to the Jan 5th layer. The crown ranged from 6" to over a meter deep in places.           (SS-ASr-R2-D2). Safe to say, we skied very low angle terrain today.