File this under #Minnesota problems:

I opened my window for 10 minutes to get some fresh air into the house.

In that time, some ice formed on the outer windowsill (inaccessible without removing the screen), and now I am unable to close my sideways-opening window.

It would be preferable to somehow fix this before the baby gets home...

@wrigleyfield I see you've gotten a lot of useful advice already. The proper Minnesotan advice, though, is to tough it out, not complain, and make sure you check the temperature at its lowest to casually drop it in conversation.
@adam42smith Yes, this checks out.