Southeast of Geneva, the most famous off-piste route in Chamonix is the Vallee Blanche starting from the summit of upper Aiguille du Midi cable car. The Vallee Blanche is an unmarked, ungroomed, off-piste route descending 2,000m over 19km with much of it on a glacier. It is an amazingly scenic ride over Glacier du Geant and Mer de Glace past ice sculptures and crevasses. In addition to the dangers of the route, it can be challenging for snowboarders to maintain enough speed to make it through the flat sections without a lot of hiking (especially near the end). This route typically takes 4 to 5 hours with the first 30% all above 3,000m elevation, which can be very cold. In big snow years, it may be possible to access with climbing and hiking another 5km and 800m of vertical descent at the very end of the route that leads all the way down into Chamonix.
The adventure begins by taking the two sections of cable cars (reservation maybe required) up to the Aiguille du Midi (3,842m). This is a very high elevation for most people and some experience shortness of breath. For early morning ascents, the summit is usually quite windy and very cold, typically 0F or below. From the cable car station, you will proceed outside across the metal bridge leading from one spire of rock to another. The exit onto the snowpack is through an ice cave which terminates at a gate with signs indicating the dangers ahead. Passing through the gate, you will need to walk down a narrow ridge line that is usually equiped with fixed ropes on either side (crampons are highly recommended). On typical mornings, a heavy wind will be blowing ice particles at you as you try to descend the ridge line for about 300m along to the start of the skiable route. The starting point is usually wind-scoured down to icepack, so you probably will not see any other tracks heading down to the northeast.
Try to start the route as early as possible and definitely do not start past 1pm. Occasionally, the route has a firm base similar to a groomed piste; othertimes it has a breakable crust or icy moguls. During very deep snow conditions, it is possible to make it all the way down to the valley, but many people descent only to Montenvers and take the train back to Chamonix (you will need to ascend a series of staircases to a small lift up to the train station).
If you do choose to snowboard the whole way down to town and the snowpack permits, at the access to the Montenvers railstation, continue snowboarding down the glacier and then climb the boot track up the lefthand slope. There will be a 10 minute walk along a track to snack station (buvette); snowboard down from there to the Planards Ski Area assuming that it is covered in snow.
There are generally four main routes down from Aiguille du Midi. The classical regular route (classique) is known as the voie normal and is the standard route of hired guides. After descending the arete ridge with crampons to the point where you can put on your snowboard, the voie normal route drops down a wide open face with views of Mont Blanc and then onto the Col du Midi which follows a large rock face called Le Gros Rognon. The route also passes numerous crevasses, seracs and ice falls. The route veers to the right following the cliffs of Mont Blanc du Tacul. From here, the route generally heads down but does criss-cross to avoid crevasses. Then a big leftside traverse begins. After the traverse, the terrain narrows considerably due to crevasses on the right and cliffs with seracs on the left (not a good place to hang around). This narrow section can also have a lot of moguls. At the end of the seracs, there is a view point known as salle a manger where most people stop for lunch. Alternately, you can traverse left and then do a five minute hike to the Refuge du Requin (a good place for lunch). The final section before the Montenvers train access is the flatter Mer de Glace, which may require some criss-crossing to avoid crevasses. By the way, an experienced snowboard-specific guide may deviate slightly from the classic route to stay high on the flatter sections to avoid hiking.
There are three other much more challenging routes that involve dropping into couloirs: Le Vrai Valley Blanche, the Petite Envers du Plan, and the Grand Envers du Plan. Also, a lesser known challenging route is the Glacier Rond. They all require serious and complex route finding down sustained steep pitches.
And, there is one more alternate route for the less serious splitboarder. How about heading over to Italy for lunch? This route still requires a guide, but try dropping down the standard Vallee Blanche route until it veers to the left. Then put on the skins and climb up about 300m to the Col de Toule (you might need a rope and harness to get over the cornice. Next, snowboard down the Toule glacier for 1,200m of vertical. After lunch in Courmayeur, head back up the cable car to Punta Heilbronner and head down the north-facing La Vierge to rejoin the standard Vallee Blanche route at the Geant icefall. Better get an early start!
Note: It is recommended to do this route on weekdays to avoid big crowds on the weekends. Even then, the first couple cable cars heading up in the morning will be jammed with skiers and ice climbers.
Chamonix has legendary couloirs with many kilometers of untracked powder descents, including several steep and deep backcountry routes from atop the Aiguillle du Midi. Most of the runs demand years of expertise, skill and nerves of steel. With all the glacial crevasses and cliffs, it is highly recommended to use a qualified guide when exploring the Chamonix backcountry. There are great guides with the Compagnie des Guides de Chamonix. If you are looking to start in the backcountry and have done the Valle Blanche, try the off-piste descent of Pas de Chevre.
Overall, in light of the cost and all that is involved getting to the start and getting out of the Mer de Glace, many feel the same 2,000m vertical descend from the Grand Montet tram car summit adjacent to the Argentiere glacier is quite scenic as well. If you are committed to the Vallee Blanche, make sure you have the appropriate gear, including beacon, shovel, probe, climbing harness, water, food and very warm layers such as a down jacket.
To reach the Chamonix valley from Geneva by car, head southeast on Route A40, and then southeast on Route N205 into Chamonix.
If you are looking for some apres ski action in Chamonix, try Chamouny, Brasserie de Rond Point, Irish Coffee, Chambre Neuf, Micro Brasserie Du Chamoni , No Escape, L Adventure or La Terrase. For some nightlife in Chamonix, definitely check out Bar de Moulins, Arbat, The Blue, Choucas Video Bar, Le Pete disco, Le Cantina Club, BPM Night Club, Bushwacker or Wild Wallabies Bar.
If you are looking for a good lift pass deal, consider the Mont Blanc Unlimited lift pass for six days or more that provides access to all the Chamonix valley ski area lifts including Aiguille du Midi, all the Courmayeur lifts with a free shuttle bus from Chamonix, and Les 4 Vallees around Verbier, Switzerland.
By the way, when you check in to your hotel in Chamonix, make sure to ask for the free guest card called Carte D Hote that provides free access to the ski buses and train in the valley. During hours of lift operation, there are regular buses between the ski areas at least every half hour, while the train tends to run once an hour. When snowboarding and freeriding internationally, it is important to get a travel insurance policy that covers emergency rescue, medical expense and evacuation. There are many destinations that will not initiate rescue or medical treatment without prior payment or proof of insurance. In many cases, the rescue fees, medical fees or evacuation to a reputable hospital can total tens of thousands of dollars. Plans such as GEOS SAR100 or IMG Patriot Travel Medical Insurance are well worth the per-trip cost of $130 to $200 USD.
Overall, Vallee Blanche is the 2nd most popular snowboard & freeride destination of all 42 snowboarding resorts in France.