A third of all US bank branches could feel tropical storm force winds from Hurricane Florence

• Hurricane Florence has started to hit the US East Coast, with rain and tropical storm-force winds spreading along the coast of North Carolina, according to the National Hurricane Center.
• Over the coming days, more than third of US bank branches could face tropical storm force winds, according to data complied by Qlik.
• Only 1,713 of those face a high risk of seeing tropical winds.

Hurricane Florence has begun thrashing the East Coast, and experts say the storm could unleash catastrophic flash flooding and storm surges as high as 13 feet.

More than five million people were under hurricane warnings or watches as of Thursday morning. Already, the hurricane has triggered more than 1,000 flight cancellations and the closing of nearly a dozen airports in North Carolina and South Carolina.

Millions of people could see their financial services disrupted, too.

More than 30,000 US retail bank branches - 34% of the country's branch network - are currently at risk of facing tropical storm force winds from Hurricane Florence over the coming days, according information compiled by data analytics firm Qlik.

Qlik analyzed branch data from the Federal Deposit Insurance Corporation and compared it with the National Weather Service's storm-path forecast and the probabilities that certain areas would see tropical storm-force winds.

While more than a third of US bank branches could feel the brunt of Hurricane Florence, the chances aren't high for many of them - for over 14,000 the probability is less than 5%.

Only 1,713 branches face a high risk - a probability of more than 60% - of facing intense tropical winds.

But for those that do get hammered, customers could lose access to their local bank's services for days or weeks, depending on the extent of the damage.

Even with millions of customers embracing mobile and digital offerings from banks - like peer-to-peer payment platforms such as Venmo and Zelle - many still take out and deposit cash in person or get paid via check rather than direct deposit.

Many banks waive ATM and other fees for customers affected by severe storms, as well as deploying mobile bank units to heavy-hit areas.

BB&T, which is based out of Winston-Salem, North Carolina and operates 1,900 branches across the country, is likely to be among the most affected by Hurricane Florence. It had closed more than 160 branches or ATMs by early afternoon Thursday, according to their website.

PNC, which also has a substantial presence in the Carolinas, has also begun closing branches and is preparing to deploy mobile-banking units.

"We have begun to close branches and other facilities in the Carolinas, Greater Maryland and Greater Washington areas, with the vast majority in the Carolinas at this point," a company spokeswoman told Business Insider.

For customers in the path of the storm, the FDIC recommends making physical copies and digitally storing sensitive documents.

Read the rest of the FDIC's tips for financially surviving a disaster.