In reply to Robert Durran:
> There are probably good reasons why not, but why not just build a new route entirely up the right side of the couloir?
The couloir continues on down a fair way, you'd have to start potentially somewhere beyond the Bionassay glacier, and or cross it at some point. Not sure how safe or easily crossed its upper reaches are. It wouldn't be hard to swing up from the valley bottom to the right of the glacier though as there are masses of trails, it just getting back on route might not be easy. Better to climb Bionassay before MB.
Better still is perhaps to either cut loses and close the hut entirely (remove it), or close in July to Sept. Logistically hard to close a route, but removing the hut would drastically reduce numbers.