Slushy, slippery roads and a jackknifed truck in the northbound lanes of the Coquihalla Highway in British Columbia caused a major chain-reaction crash, injuring dozens.

Close to 30 people were hurt in the collision that happened around 6:30 p.m. Wednesday, at exit 355 for Inks Lake Road.

A man who witnessed the pile-up says the road was more like a skating rink when the crash occurred.

Guillame Allard says the incident began when a semi-trailer clipped an SUV.  As the truck driver got out to speak with the other driver, Allard says the man was hit by an oncoming tour bus and then a logging truck piled in, dragging the victim for at least 15 metres.

Pictures in the Kamloops Daily News show emergency crews pulling seniors from the bus out the front window of the vehicle, as thick snow fell onto a snow-covered road.

There were more than 30 people in the tour bus; B.C. Ambulance reports 22 patients were treated at the scene, five of them injured critically, including the truck driver struck by the bus.