In St. Petersburg, Fla., poised to take a possible direct hit from Hurricane Irma, officials were bracing for the onslaught expected late Sunday.

The St. Petersburg police chief announced in a statement that a curfew would begin at 5 p.m., and Mayor Rick Kriseman warned that first responders would not be able to respond to emergency calls once winds reach more than 40 mph. Those services would “return when conditions are safe,” Kriseman told the Los Angeles Times by phone. “All residents need to be off the roads and taking shelter.”

Pinellas County Sheriff Bob Gualtieri’s staff was busy relocating 1,000 inmates from the county jail.

Between St. Petersburg and Clearwater, which make up two-thirds of the Tampa Bay metro area, roughly one million people live in neighborhoods that are close to waterways and are especially susceptible to flooding.

Sheriff’s deputies were already blocking access to the barrier islands that make up part of the county’s living areas.

In addition, Gualtieri was restricting access into all entry points of Pinellas County until a damage assessment and safety inspection could be carried out, according to a statement just after 1 p.m. Sunday.