We were planning on going to Lake Powell in Utah this week, but the weather is terrible. What can we do?

instead on short notice? We would like to go somewhere within about a 6-8 hr. drive from Salt Lake. It has to be either south (due to the cold northern weather) or not be weather dependent. We've done the whole southern Utah thing, so somewhere else would be nice. Our budget is about $600 for 5 of us for 3-4 days. We would consider flying somewhere with cheap tickets from Salt Lake to wherever.