In order to climb Montblanc you do not need too much knowledge of mountaineering. On a good day, everybody could hike up there with his dog. The problem is: Whenthe shit hits the fan, it is hitting it hard. You need a lot of knowledge in order to escape properly.
The Bosses ridge is narrow, but you should in most times be able to walk on the top, staying on one side. In case of climbers coming your way, you might need to step out of the steps though.
So climbing Montblanc usually involves reserving a bed in Goutier Hut and going via the Bosses ridge or sleeping on Cosmique hut and climbing via the shoulders of Tacul and Maudit. In both cases you will probably enjoy a night in a packed and crowded hut with hardly any sleep, leaving around 2am. Dont even try to race mountain guides and their clients, but walk your pace and remember: it is going to be a long day. Mountain guides run up the mountain so many times per season, that they can literally drag their clients up, regardless of their age, weight or fitness level
Also, when on the Maudit route, stay clear of them on the Maudit shoulder, they climb without any belays and you are risking being caught in a fall. You have to bring two ice screws in any case for a potential crevasse rescue, but don’t count on it on Maudit. The snow will most likely not hold it and there is too much snow to reach the ice underneath.
Speaking of crevasse rescue: this is a mandatory drill in the preparation for the climb. You have to know the basics, just in case. There are some crevasses along the way and just because it is a path everybody walks does not mean a snow bridge cannot collapse at any time. You also need to know basic belaying techniques in snow and ice (for the Bergschrund on Tacul and Maudit shoulder).
Montblanc can be compared to Similaun on steroids, if you like. A weekend on Martin-Busch-Hütte can give you a first test of fitness and rope handling. Learn the theoretical background about glacier walking and crevasses.
When going via Goutier, you might want to consider Hochkalter-Überschreitung or even Watzmann-Überschreitung. Both tours are long and demanding, giving you a sense of 10-12hrs tours. You have to learn to maintain focus over that time.
Although I did it in winter, I believe Piz Palü is a good test for altitude, learning how your body reacts at close to 4000m.
For the last 300 vertical meters on Montblanc we needed about an hour. During a normal day on Herzogstand we were able to cover more than 600 vertical meters an hour without pushing it.
You also need to walk a lot with a backpack. The method described in Steve House’s book „Training for the New Alpinism“ is awesome: pack water bottles and head for a hill. On the top just pour out the water and have less stress on your knees when you walk down. I also thought about bringing beer and selling it at the summit, thereby financing the expedition.
Having a strong core also is important. You will be carrying a pack for quite a while, make sure you can. I never actually liked training the core, but the effect is amazing. After doing it a while it really paid off.
Just now I realize that I did not cover walking with crampons. Most likely because walking on the Bosses Ridge demands such a perfect control of your crampons, it needs no further expression. On the three mountains you will have to climb with the crampons, so it’s even more important.
When the shit hits the fan, there is zero margin for error. Many sources underline that even on sunny days the temperatures near the top can be in the double digits below zero. The wind will cool you down. If somebody is not used to alpinism and the suffering that can come with it, things might go south pretty quickly, because retreat will always be a challenge in itself. There are not too many options to escape both quickly and safe. For most aspirants a proper risk assessment is what I consider the biggest challenge.
Overall, climbing Montblanc on a good day can be great fun. Just make sure you are well prepared and the weather is favourable.
You can find more photos and the report of my tour here: Tour report.
The conditions on the mountain can be found here: Office Haute Montagne Chamonix.