Never have had such happen here in Panhandle of Texas.....yet !....:o)
Most of power brownouts and storms are localized, as in one is back on before the other goes out per se..... so NG is not interrupted in such a manner I am guessing.
Our basics are woodstove, oil lamps, convection cooling, and vehicles with the power inverters for emergency needs. Water is stored, 2 large katdyn expedition water filters allow us to rob the rain barrels, swimming pool and jacuzzi if needed for potable water. Also use a old pressure cooker for distilling water. Adhoc still per se.....suspect water in, steam out, condenser coil of copper tubing, clean water drips out.
2 large manual pump bug sprayers we use for showers when camping with the water saver heads on em fill the emergency shower system task. I used such in the desert w/ fogger heads for evaporation cooling as well. That of course takes a low humidity area to work best.
Just some ideas.....:o)
I have very similar stuff! I like the bug pump mist cooling idea for the summer. We are in an arid area so it would work well. We live next to the Columbia River and so have a huge source of easily-filtered water. Many times, filtration would not even be strictly necessary out away from the banks.