Luke, they still respond to local disasters (and/or riots too) and I've actually have had some experience in this as an active commander of one of these reserve forces centers about 5-6 years ago. Example: In the case of the flood, the local NG troops (but not Reserves) get called in and put on a spreadsheet. The spreadsheet goes to the state payroll office and the state pays them - though not nearly as much as when federalized. Pretty simple and it's meant to be since it's an emergency. States and federal can call up NG but only federal can call up the Reserves. There's a little wiggle room in there since Katrina but more minutia than anything else - everyone has a rank regardless of status. Now those states with an additional state guard cannot have them called up by the feds, but they aren't supported by fed $$ in anyway either, it's purely state and often out of their own pockets. Unlike NG or Reserves who get a partial paycheck/bennies and fully equipped through the regular military.
State mobilized troops are then put under control of the sheriff or supervising state trooper (varies by state). Again this happens very quickly but the state pays for the fuel, food, etc.. (though using equipment given to them by the feds).
When they get deployed and federalized as part of the regular military, it is now a well-planned process where the payroll goes to the federal base, they get a proper train-up even before leaving home, re-swearing in, more training, full fed pay/bennies (as required), and in the case of NG, leave a sizable contingent back at the home state, etc....
It's no longer, "hey you in the green!!!" ... usually.