Some simple bolts, some reclaimed wood, and some plywood sheet made what is essentially two swing-up doors that are slanted so rain and snow slide off of them into the yard. Because the wood isn't perfect, the rain runs right down the wall into the drain below - that means I haven't changed my drainage. Woot!
It wasn't that hard a job but it was damp and icky and I was very glad to have a friend come out and help!
I put some of the split foam "pool noodle" style pipe insulation around most of the edges to keep things from bumping and scuffing the side of the house. This also seals the doors against the side of the house - not to mention the gap between the two door panels. The one door has a warp to it so I will, hopefully tomorrow, screw a short 2x4 to the back of it to straighten it out and weigh it down a bit.
The final things to be done are to seal off the one end butting up against the deck so no airflow can go through there, then seal anything else with spray foam. Final item will likely be some kind of heavy "skirt" on the back stair edge. Something that will hopefully discourage animals from hiding down there and close out the last of the wind.
Bonus point: I don't have to take the storm door off after all! It actually swings all the way out without hitting the overhead doors. Sweet! Guess I'll keep that door after all. Probably figure out if I have the proper screen or glass for it finally.
Cross-posted from Dreamwidth ( http://nimitzbrood.dreamwidth.org/280100.html ) but feel free to comment here as well.