Cornices are beautiful snow features to look at from below but are deadly to cross. Cornices present a substantial hazard to all types of mountain travelers. Probably the most dangerous aspect of a cornice is that you will likely not know that you are standing on one until it breaks from underneath you. When that happens, you will most likely not survive. Mountain Skills Academy has an excellent discussion of cornices on their website.

The summit cornices on 9709. Bob Boyles photo

Sometimes you can spot an upcoming cornice but most of the time you will not. Bob Boyles Photo