Was Wizz Air right to deny compensation to passengers stranded by the Barcelona flight cancellations?

Wizz Air cancelled its Barcelona flights over the weekend due to a storm; affected passengers can't get home before Wednesday, and the airline cites extraordinary weather to avoid paying compensation.

• Yes, the storm wasn't the airline's fault
• No, they should have at least covered care and accommodation
• Partly: the cancellation was fair, but the communication was unacceptable
• Can't decide, I don't know enough about the rules