I wish I had taken some pictures when this happened, but suopsed I was too busy recovering. It was at Corbin, Ky KOA and the site was a little small for my trailer and the truck was pointing slightly downhil - which kicked the hitch end up higher than normal. The trailer tounge jack already won't lift the trailer high enough to hitch so I'd built a sizable stack of wood and plastic pieces to hole it. I got the truck unhooked and was putting some stuff away when it slipped off the stack. So the uphill wheels were chocked, on the downhill side I'd pulled up on 3 or more inches if wood and plastic - but didn't chock it. the nose of the trailer just went down hill and rotated the trailer about the chocked wheels. I'll replace the jack when i get to Michigan. I purchased a small bottle jack to keep in the trailer in case something like that happens again.