That's why banks are trying to ensure there's enough cash available for residents in the Gulf region on the expectation that Hurricane Gustav will hit.
JPMorgan Chase & Co., for one, has been coordinating with its armored truck vendors to make sure there is plenty of cash on hand at its branches and ATMs in Louisiana, spokesman Tom Kelly said Friday.
Ahead of Hurricane Rita in 2005, Kelly said JPMorgan Chase saw huge demand for cash in the Houston area as people prepared to evacuate. Rita arrived on the heels of Hurricane Katrina, which battered New Orleans exactly three years ago.
At the time, institutions including Bank of America Corp. and Citigroup Inc. deployed mobile banking centers to the Houston Astrodome, responding to people's need for cash at that temporary shelter for evacuees.
Charlotte, N.C.-based Bank of America does not have branches in Louisiana, but it does in Texas and Florida. Spokeswoman Britney Sheehan said that, like many other banks, Bank of America has assembled a regional support team to monitor Gustav and prepare for a potential strike.
Citigroup and Wachovia Corp. also said they have pre-planned disaster procedures in place.
It's not just financial institutions making sure there will be enough cash for customers to use - some retailers are doing the same.
Target Corp. spokeswoman Brie Heath said the Minneapolis-based chain was working to get extra cash to its Gulf Coast stores by Saturday - a challenging task in the hours leading up to the long holiday weekend.
But Heath said company was confident its stores would be prepared with cash on hand, after learning the importance of stocking up on paper bills in the aftermath of Hurricane Katrina.
Banks are also girding for the possibility of having to close down certain branches and extend the hours of others. After Katrina, Chase kept some branches in the surrounding areas open for 23 straight days, even Sundays.