We have the same problem. I can't get out to where my horses are kept as every road is closed. The farm owner said the barn is nearly a foot deep in water and there is no dry place in the pasture. He was going to ride their mare and pony my horses to a neighbors' field, then saw the horses trying to walk across the ice under the water surrounding their barn and they kept falling
He took the horses up to the machine shed and tied them in there for the night with hay and water. Ideal? No. But at least they aren't in knee-deep, frigid water or skating on the ice under the water. They're shivery and wet, but drying out and it looks like all are standing well on all four legs and eating and drinking, so hopefully nobody was badly hurt.
A friend of ours is currently trying to get 450 cattle out of a corral that is 4 feet deep in frigid, icy water that wasn't there three hours ago. He can't get trailers or semis in to them, so they're trying to drive them along the road and around the flooded spots to safety.
It's a mess. I've never seen it like this. More rain and 65 mph winds tomorrow will not help. Our entire neighborhood is a lake, and we are on the HIGH PART of town. So many people dealing with flooded basements.... heavy rain with no end in sight on top of a record winters' snowfall is causing a huge issue. The normal culverts, drainages, and waterways are all clogged with snow so water has nowhere to go.
Can you move your horses to somewhere dry? A garage or shed? A neighbors? Horses can end up with nasty skin infections from standing in water too long. I wish you well. All of us in the midwest are dealing with this and it sucks. I would have to guess that the ten round bales we still had in the barn, even though up on blocks and pallets, are all ruined now, too, so everyone will be scrambling for hay after this, and there just isn't any and won't be until June.