Bet you sprayed water on or around the gas cap area? If you look closer there's a small opening to the right of the cap that's the air intake for the carbon canister that hangs under the spare tire well. You just happen to catch the evaporative system while it was in a test mode and/or the canister was being purged. Don't spray water in that opening it's possible to suck water into the canister and then into the tank/and/or engine.
Just recently did it myself and an engineer at Visteon told me not to be spraying water into that opening.
I wasn't into removing the tank to find out, I just poured a whole can of system cleaner (out of dry-gas) to make the water mix with the gas. No problems, no ice-up during the single digit temps.
Paul
