BOSTON -- Heavy snow and slippery roads may have played a part in a bus crash on the Massachusetts Turnpike on Sunday night.

Bus Skids, Crashes Down Ravine | Crash Images

The Morning Sun coach bus crashed into a ravine carrying 31 passengers and emergency crews were still at the scene early Monday morning on the westbound side of the Turnpike in Grafton.

Jian Kang Chen, 51, of Quincy, was driving the bus from the Boston area to the Mohegan Sun Casino in Connecticut.

It was unclear exactly what caused the accident, but roads were slippery from heavy snowfall. The bus went off the road shortly after 11 p.m.

Five passengers suffered neck and back injuries and were taken to UMass Medical Center in Worcester, police said.

"I was panicking. I was really, really scared," passenger Jackie Clark said. "I was sleeping and felt the bus skid. It kept turning and turning and then did a nose dive."

"There was a long process -- a lot of personnel. We had to use ropes and sleds to carry the people up. On a night like this with only five injured, it is a miracle," Grafton Fire Department Chief Michael Gauthier said.