For some entrepreneurs, Mother Nature is also the mother of invention.

From floodgates for homeowners to "diapers" for absorbing storm waters,they've come up with ways to tackle the problems brought on by tornados and other major events-including, of course, Hurricane Irene.

"Often large disruptions such as natural disasters create the basis for new business opportunities," says Andrew Zacharakis, a professor of entrepreneurship at Babson College in Wellesley, Mass. From The Wall Street Journal.