Watch out for cornices, and avoid them at all costs.
"Cornices are hands-down the most dangerous feature in the backcountry," warns Travis. "They inevitably take the most people out." A cornice forms when you have one consistent wind direction blowing over ridges that inevitably scours snow off the windward side and deposits it on the leeward side. You end up with overhanging, unsupported, unstable accumulations of snow. It's virtually impossible to predict when these things are going to fall. So when traversing in the backcountry, you should always be aware of what's above you, such as cornices that can break off at any time. Never walk up onto a ridge to look over the other side unless you're sure that there's no cornice.