Running a heater takes major wattage. A battery backup will only take you so far. People need to be making a bugout plan if they don’t have an alternate means of heating their home for at least 72-hours.
Also, it shouldn’t need to be said but running a gas stove or propane heater indoors is a no-go.
[EDIT: same goes for generators!]
People: remember to shut off your main water supply and open a few faucets before you go.
[EDIT 2: and go fill up/charge your cars NOW]