Are they out of the race?
No. Azzam will be returning to Alicante to fit a new mast and will resume racing when it gets back to the place where the mast snapped. That might take three days.
How common is demasting?
Demasting is probably the most serious damage that can happen to a boat, short of breaking the hull. Skippers are conscious the mast is vulnerable in storm conditions, and will try to avoid putting too much strain on the mast and rigging by reefing the main sail or pulling down the main completely. Competitive sailing is always about pushing the boat to the limit. As Ian Walker said before the race: "There's a risk management in terms of performance with the boat. If you push too hard, you break something, you might have to push out of the way or you might have to make repairs."
Who or what is to blame?
It is too early to say. Azzam was built to withstand more than 40 knots of wind and, in any case, the main was reefed in at the time of the accident. There could have been a defect in the mast, or in the rigging which holds it in place. Or there could have been an element of human error.
Can they still win?
Azzam still has a chance to challenge for the overall trophy, even if it finishes near the back of the fleet in first leg to Cape Town. The race is composed of nine legs, each of which scores 30 points for the winner plus in-port races at each location with six points for the winner. Boats in lower positions still score points. Azzam won the in-port race in Alicante so it has six points in the bag. After Sanya damaged its hull, it is possible that Azzam might come in fifth in the first leg, giving the team 16 points overall for the first leg. After that, it is all up for grabs.