In one moment you can be skiing in France, the next in Switzerland, there are very few other ski resorts that can offer the same in backcountry riding.
There are several excellent guidebooks with descriptions of the many possible routes both within and beyond the lift areas. There are two published by Vamos called Mont-Blanc Ski tours (ISBN 2910672085) and Chamonix Hors pistes-Off piste (ISBN 2910672107); these books are bilingual, in English and French. A more extensive guidebook with more difficult routes is Mont-Blanc et Aiguilles Rouges à ski (ISBN 2960025520), written by Anselme Baud and published by Nevicata; it’s only available in French but is worth struggling through even if your French isn’t so good as it gives very accurate descriptions and has good explanatory photos. But remember, in the backcountry there are many dangers not least from cliffs and avalanches so you should always hire a Chamonix guide.
A favourite ski-tour is the Grands Autannes. See the route below:
It’s best to set off as early as possible because the slopes of the Grands Autannes are steep and catch the sun in the afternoon. Take the gondola up from Le Tour then the Autannes chairlift. Next comes the hard part; either on snowshoes or skins start the ascent up the slopes in front of you. Sometimes it’s best to go up onto the ridge and follow it along to the couloirs, at other times if it looks safe it’s easiest just to head straight up the couloirs. It’s a deceptive climb as it doesn’t look very steep from below, but the upper section by the GAZEX tubes can be intimidating and you need crampons for the last section. At the first saddle, head to the right up the last short rock scramble to the small peak. Once at the top you’ll realise it’s worth the climb, as you have a great view over the back to the Trient glacier.
For the descent to Trient, stay high and traverse skier’s right, avoiding the rock bands below until you reach the open bowl. From there it’s open powder all the way. If you look left you can see the Col de Balme and the restaurant there. Below that is the long gully that leads to Trient. There are several small and steep chutes that lead into the main gully or you can pick your way through the bushes. The chutes are better, but beware of wind-loading, as you can set off small slab slides. Don’t hang around in the main gully, because it is a serious avalanche channel. After a big snowfall this place is extremely high risk. Follow the big gully down, and head left at the bottom into the meadows. Follow the ski de fond trail to Trient and have a beer at the café while you wait for the bus. Job done, powder run completed.
PS. Don’t forget to take your passport on this trip as you may be asked for it when you head back over the border into France.