(CNN) -- One after the other, dozens of cars and trucks slammed into the back of a multicar crash in Massachusetts until about 70 vehicles had been wrecked and at least 35 people had been taken to hospitals, the Massachusetts State Police said Sunday.
Two people were seriously injured, Sgt. Stephen Marsh told reporters.
The accidents began before dawn on icy Highway 290, Marsh said, and didn't stop until the chaos stretched 500 yards.
Marsh said that as cars came over a rise, drivers saw the accidents and tried to brake but were caught up in the chain of collisions. Other motorists were able to see the trouble in time only after so many cars were piled up that they stretched out over the incline, he said.
There were four commercial trucks and about 65 passenger vehicles involved. One of the cars that was rear-ended was a state trooper's cruiser, which was stopped at the site of one of the early crashes.
Marsh said some of the cars were wedged under the tractor-trailers that turned sideways, blocking the roadway.
The road, near Worcester, was closed for about five hours.
A bus was brought in to help transport some of the injured to hospitals.