Just a nitpick on an otherwise excellent piece: Annapurna is actually the most lethal mountain in the world, just ahead of K2. It claims 34 deaths per 100 safe returns over K2's 29.
To climb K2 in winter is extraordinarily dangerous. It's dangerous enough in season. But the Poles are the hardest of hard men in these situations - good luck to them!
I was surprised to learn that. I always assumed it was K2 because it's widely said to be the most difficult peak to climb.
The one quote I found online from Ed Viesturs:
"Annapurna is all about objective danger, it's all about the glacial architecture. There are these big ice cliffs and seracs, and the question is: are the seracs leaning forward or leaning back? It comes down to that." His account of the Annapurna climb and his earlier failed attempt on Annapurna is chronicled in his new book, Himalayan Quest: No Shortcuts to the Top.
To nitpick your nitpick-- there are different metrics for deadliness. By sheer volume of deaths, Mont Blanc might be on top with 6,000-8,000 (estimated).
Sheer volume is meaningless unless we know how many times it's been successfully summitted. Mont Blanc is dangerous because it's easily accessible to lay people and despite being advertised as a 'long walk' can turn deadly very quickly.
Annapurna on the other hand has been climbed less than two hundred times in history, all of those people were elite mountaineers and further third of them didn't make it back.
To climb K2 in winter is extraordinarily dangerous. It's dangerous enough in season. But the Poles are the hardest of hard men in these situations - good luck to them!