The sheer size, immense weight and deadly force of tractor trailers was evident in a stunning series of violent car and truck accidents that took 10 lives on a Florida interstate highway yesterday.

The accidents involving about 20 vehicles were about 85 miles north of Clermont on Interstate 75, near Gainesville.

Law enforcement officials say they still aren't sure of the exact causes of all the wrecks, but they say that smoke from a nearby brush fire combined with fog to blanket the highway early Sunday morning.

A 19-year-old driving to Gainesville around 4 a.m. said he hit a "thick wall of smoke" on the highway, forcing him to slow to five miles per hour.

"I had to open my window and stick my head out to even see the lines on the highway," he said. "I couldn't see anything past the edge of my car."

The thick fog and blinding smoke not only made driving extremely difficult, but the poor visibility also hampered rescue efforts after officials began to get calls about tractor trailers colliding with each other and with cars, and calls about cars piling into 18-wheelers.

One portion of southbound I-75 was engulfed in flames after a semi-truck carrying tissues collided with a FedEx truck.

"I saw flames," the 19-year-old said. "We kept hearing bangs."

Witnesses said a Pontiac Grand Prix and its occupant were crushed and burned beneath the wheels of a Dodge pick-up truck. A charred body was apparently visible inside the Pontiac.

Rescue workers couldn't see accident victims; they had to locate victims by listening for their screams and groans.

Yesterday, law enforcement officials said the wreckage was strewn over a mile of the highway.

One Florida Highway Patrol trooper said it was the worst accident he's seen in his 27 years on the force.

Source: alligator.org: "Ten dead in series of multi-vehicle accidents on I-75," Emily Morrow, Jan. 30, 2012