Just be safe! No fishing is worth losing your life over. Some places I've fished the water gets so high & muddy, it's dangerous. Otherwise, as has been said, the edges are worth trying. Try something large, like a streamer. Baitfishes & smaller fish will be taking refuge too!
Feeder streams can also be good, as they'll often not be as affected by the rains as a main stem of a river might.