Days before Hurricane Florence is expected to slam into the U.S. East Coast, insurers are starting to see potential claims costs tick upward as people flee and companies halt operations.

Evacuations, already affecting more than 1 million people in and around North Carolina, start the clock ticking on business-interruption insurance policies, which help replace lost income for companies when natural disasters strike. Hartford Financial Services Group Inc. and FM Global are among insurers with exposure in the region that are sending staff to help with anticipated claims.