I should have been more precise in my previous post. Glissade simply means to slide down the snow. You can glissade standing or sitting. A standing glissade is also called boot skiing.
When I descend a snow slope, I typically use a combination of three techniques: Plunge step (as I described in my previous post), French technique (where I walk with my boots or crampons flat against the snow or ice), and a standing glissade. I switch among these techniques quickly as conditions change. This makes for a fast, safe descent. I may use either ski poles or an ice axe, depending on conditions. Crampons are optional, again, depending on conditions.
Every newbie thinks the sitting glissade is cool, fast, and fun, at least until something goes wrong. Most of us either have screwed up or know someone who screwed up doing a sitting glissade. My wife did a spectacular ass-over-teakettle when she tried it. Steve’s partner did the same. Bob West admits to a dangerous mistake on the Palisades Glacier. (It’s glissading out of control, not having a leash on his axe, that made it so dangerous.) There are countless stories of accidents (and a few deaths) doing sitting glissades down from Trail Crest. I once saw a guy spend the night in a sleeping bag on the side of the slope above UBSL because he broke his leg doing a sitting glissade. (A rescue team was there, but they couldn’t move him or get a helicopter until the next day.) And then there is R.J.Secor’s injury (in Bob West’s post). How many of you know someone else who had a bad outcome doing a sitting glissade?
As Steve points out, a sitting glissade really can be safe, fast, and fun under the right conditions. But those are the same conditions where I would basically jog down the mountain, sliding a little with each step. When I came down from Trail Crest in January 2011, Bulldog34 saw my Spot track and thought I must have done a sitting glissade. Nope! My pants were dry and my ass was warm when I got back to camp that night.