we were camped on the sand and clay around a granite rock, which can turn to mush when wet, but I thought it not that deep under the wheels, and it was an effort to move, so we stayed put. But the lightning was fearful. We climbed into bed trying to avoid touching any metal, and listened to the thunder and lightning as it surrounded us, we were one of the highest points around for miles! See reference here, with more images! earthsky.org/earth/amazing-photos-of-mammatus-clouds PA214113