I can't recall there ever being a riot after a natural disaster. Riots are mostly about theft and wanton damage and the storm has already done a lot of damage in areas where riots might otherwise be likely.

Lots of police presence and cold weather are also serious deterrents.

Wait till tomorrow though. As we know, there is one part of the political spectrum in the US that may well riot if their candidate loses [you know how them Mormons are :)]. Although, the most likely spot for a riot is experiencing cold temperatures and rain, which could well dampen the enthusiasm for rioting.