I bet that your air filter became waterlogged and when you pushed the motor harder it was sucking too much water through the filter and was choking your motor.
It fits with the facts that you were in a major storm, and removed the vent covers allowing lots of water to hit your filter and that now your car is running fine. If this is what happened and nothing happened at the time your motor should be fine. I have my right vent cover removed to feed my cold air box setup and actually experienced something like this during an extremely wet snow storm we had. I took the filter off, dried and my car was normal again. I will be getting a MRT side scoop vent soon so that it covers the vent vertically but still allows water in. After that I want to do a reverse scoop for the main hood vent.