Wheel Frozen on 2000 Dodge Caravan

We live in Minnesota and it has been below freezing for a couple of days and this van sits outside. Yesterday it was driven and was fine - then parked for a few minutes and when restarted and driven - one of the back wheels is frozen. It doesn't roll at all. What do we do?

Asked by for the 2000 Dodge Caravan
Were the parking brake applied when it happened? If yes, try to avoid them at very cold temperatures.

No - he had parked, but on level ground and not used the parking brake. We just tried driving it again and the back wheel is still locked up - we are not sure what to do at this point. Do we need to have it towed?
Try to apply the brakes 10-20 times and also try to move it back and forward You can pure hot water to the brake area also, it won't hurt anything. If this won't help you might need to tow it to a shop on a flatbed.

Thanks - this is very helpful.