Maybe the got too much water and the roots rotted - pull one out of the ground and check the condition of the root ball.

Sounds like you needed to make tomato cages from "pig fence" and wrapped with heavy construction plastic as they don't like all that wind this time of year and hail sure can do them in by its self. I wouldn't worry about the potato plants but line kayjones says, you can pull them out to check and see if they have a root problem. If so you may need to treat the soil before re-planting. Plants have almost the same effect from overwater as underwatering.