I guess I agree with the general consensus of 2-3 weeks but there are a lot of modifiers on this that haven't come up yet. I live in the midwest so there are seasonal (and scenario) variations that have to be considered. A severe winter storm that takes out power etc. is different than a severe summer storm that does similar damage.

One example to consider - running a generator for weeks in the winter can be a major effort, especially if the "Alberta clippers" keep pounding the area every couple of days with more ice, snow and cold!! In the summer you can usually run the generator for a while then shutdown a while (unless your sump pump is running flat out to keep the basement dry) but unless your house is designed to be heated without electricity you will need to run it pretty much continuously. Restoration of services / repairs always seem to take a lot longer in the winter too.

Another example - here in the midwest a winter storm might take out your power and isolate you due to snow and ice. A severe thunderstorm / tornado could have the same effect in warmer months (power lines down, trees/debris on the road or the road just plain gone) but adds in the bonus round opportunity of having your home literally blow away. That one last one is basically a call to dig out the credit cards. Luckily tornados have a relatively small footprint so supplies should be available for purchase.

So sometimes long is only a couple of days or hours "on site" and than a shift to more of a transition phase which will vary in length.

- Eric