Hundreds of closed banks along the Gulf Coast are watching Hurricane Isaac's path to see where the lights go out. If the power goes down, that means banks will start to deploy mobile ATMs powered by generators.

"It becomes a cash economy pretty quickly when power is out for extended time because you cannot use a credit card terminal," Evelyn Mitchell, a spokeswoman for Regions said in a phone call on Wednesday morning. She said it was not yet clear whether the bank would need to deploy mobile ATMs following damage from Hurricane Isaac.

The hurricane reached land on Wednesday morning, soaking southeastern Louisiana and southern Mississippi with heavy rain. The storm is expected to move north slowly and reach southern Arkansas by early Friday, according to the National Weather Service.

On Tuesday, hundreds of bank branches were shuttered in Louisiana, Florida and Mississippi, and many were expected to stay closed on Wednesday. Chase, Capital One, Whitney Bank and Regions are posting opening and closure updates on their websites.

Credit unions were also closed along the Gulf Coast on Wednesday and a few planned to reopen Thursday, according to the Credit Union Times.

Chase Bank announced Tuesday that it would waive certain fees for customers in Louisiana and Mississippi through Aug. 31, including overdraft fees and late fees. The bank said it would also waive fees associated with non-Chase ATMs through Friday.

Regions' Mitchell said the bank offers disaster assistance, including fee waivers and deferrals on personal and business loans, but did not specify a time frame for that assistance. The Federal Insurance Deposit Corporation, or FDIC, also posted an emergency resource page to provide guidance for people affected by the storm.

Standard storm preparation advice suggests that residents stock up on cash in case electricity is slow to return to a community. The emergency website Equipped to Survive recommends $100 in cash per person and a roll of quarters.

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