Residents along Florida’s Gulf Coast were fleeing in droves on Tuesday ahead of Hurricane Milton’s predicted landfall, in what officials said was likely to be the biggest evacuation the state has seen since Hurricane Irma struck in 2017. Evacuees have faced hourslong traffic jams on highways and gas stations running out of fuel.

Nine counties in Florida, including some inland ones, have ordered mandatory evacuations for Milton, the strongest Gulf storm since 2005. Officials were preparing for “the largest evacuation that we have seen, most likely, since 2017’s Hurricane Irma,” Kevin Guthrie, the executive director of Florida’s Division of Emergency Management said in a news conference on Sunday.

That storm prompted the largest hurricane evacuation in the state’s history, with about 6.5 million people fleeing their homes.

Officials have warned residents in evacuation zones to leave as early as possible to avoid traffic jams. “This will be one of the largest evacuations along our state’s west coast. If you wait, you will get stuck in traffic,” the government of Sarasota County, which issued evacuations orders, said Monday on social media.

But those who fled north on Monday were already reporting heavy traffic, gas stations that had run out of fuel and trips taking several hours longer than usual.

Jacqueline Camenisch, 62, from Kentucky, cut short her family vacation in Orlando and drove north on Monday evening with her children and grandchildren to Panama City. She had initially wanted to evacuate the family to Gainesville, about 100 miles north, she said, but found that all accommodation was completely booked.