The crashes set some of the vehicles on fire. One of the first to burst into flames was a FedEx truck, Forgy said. It likely began a "domino effect" with cars and trucks going from nearly 70 mph to a dead standstill in seconds. Vehicles ended up spearing others, pancaked under semi trailers and stacking up on each other.
The vehicles were so mangled and so charred that it took investigators more than 24 hours to identify the dead. The scene was so chaotic that investigators are still trying to determine the chronology of the accident.
Lt. Pat Riordan of the Florida Highway Patrol said "this was the worst I've seen in 27 years on the job." When rescuers first arrived, the superfog and smokefog were so thick they had to locate victims by their screams.
The Florida Highway Patrol and various sheriff's offices continue to investigate the crash.
The Associated Press contributed to this report