gas station
People line up to fill their cars with gas after South Carolina Gov. Nikki Haley ordered a Wednesday afternoon evacuation of statewide coastal counties in anticipation of Hurricane Matthew in Myrtle Beach, Oct. 4, 2016. REUTERS/Randall Hill

Multiple counties in Florida and South Carolina have ordered their residents to evacuate on a voluntary basis, but a handful of others are under mandatory evacuation orders as Hurricane Matthew bears down on the U.S. Failure to comply with the order could mean the difference between life and death, state and weather officials said Thursday.

"Extremely dangerous and life-threatening wind is possible," National Weather Service's Melbourne office said. "Failure to adequately shelter may result in serious injury, loss of life or immense human suffering."

According to the Federal Emergency Management Agency, residents under evacuation order should "Listen to instructions from local officials and be prepared to evacuate when they tell you to do so."

A mandatory evacuation is defined as "a situation where emergency management officials put maximum emphasis on encouraging evacuation and limiting ingress to potentially affected areas," according to USLegal.com.

However, despite the term's name, mandatory evacuation orders are not technically mandatory. They are simply the strongest suggestions implored by local officials.

Florida Gov. Rick Scott all but echoed that sentiment, especially as it pertains to thrill-seekers who may be looking to confront the Category 4 storm with winds of up to 145 mph. Forecasters are predicting there is a strong likelihood of it becoming a Category 5 storm, which is the most severe and strongest designation for a storm, NBC News reported.

"Do not surf. Do not go on the beach. This will kill you," Scott said during a press conference Thursday morning. "There is no reason not to leave."

Hurricane Matthew's wrath has already left at least 25 people dead in Caribbean nations, including Cuba and Haiti.

More than 2 million Florida residents have left their homes, CNN reported. The National Guard has been dispatched from the northern part of the state to the southern tip. Many flights have been canceled, leaving highways as the prime method through which to evacuate.

To encourage residents to evacuate, the state has temporarily eliminated all toll fees, including popular thoroughfares such as Florida’s Turnpike, Alligator Alley and the Miami-Dade Expressway Authority, the Palm Beach Post reported.

South Carolina Gov. Nikki Haley said evacuations there began Wednesday afternoon, but she stressed to not pay attention to semantics surrounding the state's orders to residents, according to U.S. News & World Report.

"We don't do voluntary or mandatory. It is an evacuation," Haley said Tuesday. "Our goal is to make sure you get 100 miles away from the coast."

Hurricane Matthew is expected to make landfall late Thursday night.