Crevasse risk: when we were there it seemed minimal if you stayed on route. But almost everyone was roped up. The guide said sometimes a climber would drop in a shallow crevasse. If you were to get off route, there were places that could swallow you never to be seen again.
Here’s my trip report. I was happy with our guides. http://www.summitpost.org/elbrus-north-route/726384
We went with Elbus Tours, also known as Over the Rainbowhttp://www.elbrustours.ru/en/
Another company a lot of people seem to use is Pilgrim Tours
I originally booked with them, but when things fell apart for south side access they refunded my money since they weren’t prepared to offer a north side itinerary on our schedule.http://www.pilgrim-tours.com/index.shtml