A Key West woman was killed Tuesday morning in a single-vehicle crash at Mile Marker 98 in Key Largo, according to the Monroe County Sheriff’s Office.

The crash occurred after 5 a.m. in the southbound lane of U.S. 1, and Sheriff’s Office personnel responding to the scene reported a full roadblock after 6 a.m. By 9 a.m., traffic was moving on the highway but backups caused extensive delays.

Sheriff Rick Ramsay, traveling to the site, told U.S. 1 Radio early Tuesday that traffic near the crash scene was backed up at least five miles, with vehicles being diverted to a bike path.

According to Ramsay, the vehicle involved in the crash was traveling in excess of 100 mph.

“The vehicle appeared to have lost control and crashed into a large amount of stuff,” Ramsay said, noting the vehicle struck “a large boulder, telephone pole guide wires, palm trees, fences.”

Ramsay said he was told the car flipped multiple times, and the crash was “so severe that the vehicle was torn into, I’m told, three separate pieces.”

The sheriff said the crash was being treated as a crime scene and Florida Highway Patrol was taking part in the investigation.

“The crime scene is so intensive, with car debris, parts and, sad to say, even body parts are on the road,” Ramsay said.

Three Upper Keys schools — Key Largo School, Plantation Key School and Coral Shores High — were closed Tuesday because of the accident, which caused power outages, according to Becky Herrin, spokeswoman for the Monroe County School District.

The driver’s name and other details of the crash were not immediately available.