Sandy flood
A general view of submerged cars on Ave. C and 7th st, after severe flooding caused by Hurricane Sandy, on October 30, 2012 in Manhattan, N.Y. - 

Early estimates of the economic damage done by superstorm Sandy range from $20 billion to $50 billion. That would place in the top-five of America's costliest storms. Analysts figure insurance coverage may pay for half those costs, or less.

A big wallop this time is business interruption: buying, selling, shipping and manufacturing that didn't happen. This storm hit on a particularly bad day on the calendar: a work day.

"Hence its impact is very likely to be much more severe than that of Hurricane Irene," says IHS Global Insight economist Greg Daco, "which had a similar trajectory in 2011, but hit us on a Sunday,

Big companies insure again disruptions. But small firms don't. Nor do hourly workers.

"If they're not working they are not getting paid," says Chuck Watson of the hazard research firm Kinetic Analysis.

"They make some of it back in overtime, but for the most part that's just lost wages for them. You throw in maybe some child care because school's out, and you've got a lot of stress on people just getting by, and on your medium and small businesses."

Also on the hook big-time: governments. They own the subways, roads, bridges and street signs that need fixing. The federal government can borrow and run deficits; state and local governments can't.

"Local officials are faced with a real dilemma," Watson says. "Do you raise taxes? Maybe that pothole in front of the high school doesn't get filled in for an extra month or two, or maybe there's a program that you don't expand."

As for homeowners, insurance covers wind damage, but not flood coverage. If they have flood insurance, Washington picks up most of that tab.

Going forward, Watson thinks private insurers will get more and more out of the catastrophe business in general. He says they find it too unpredictable.

If that's the case, then having a piece of the rock will be a smaller piece of the pie when it comes to disasters.

Follow Scott Tong at @tongscott