Can't imagine pets being permitted in the shelters -- what a mess that would be. My guess is that plenty of food and water left for them in the highest room in the house would be all you could do. Then just pray they'll be okay.
Pets are NOT allowed in shelters. No doubt some people won't go to shelters because of their pets.
Pets are very resiliant. If there is a way for them to survive, they will. Remember the cat they found on the roof of an abandoned building six weeks after the World Trade Towers went down. The owners couldn't get back to their apartment and figured the cat was gone. It had lived on rain water and...?