Okay finalizing our preparations here--need animal question answered

[Horse with no Name]

I have an outside dog.
He cannot come in under any circumstances. He snaps at the baby, and I can't bring him where he might hurt her, especially if he is scared.
I have an alcove off my back porch--I had removed the screen so the dogs could lie up there during the winter--there are rugs and blankets and a bale of hay for their warmth.
We will probably have some flooding--but my house is on pier and beam so we are off the ground.
My question is--do you think if I put plywood over the screen door and left a small area for him to get in and out of...that it would be okay?
Or does anyone else have any other suggestions?