KAMLOOPS, B.C. - Single lane traffic finally began moving on the Coquihalla Highway, just south of Kamloops, B.C., shortly after 5 a.m., nearly 11 hours after a major chain reaction crash shut down the northbound lanes of the route.

RCMP say the crash occurred just before 6:30 Wednesday night when a tour bus hit a jackknifed transport truck, and another semi-trailer and at least two cars rammed the wreckage.

But witness Guillaume Allard says the incident actually began when the first big rig clipped an SUV, and the semi driver was out of his truck and talking with the other driver when he was hit by the northbound bus.

Allard says a logging truck then slammed into the back of the bus, carrying that vehicle and the truck driver at least 15 metres down the very slushy and icy highway.

Allard believes the truck driver suffered at least a broken leg but RCMP say all other injuries — including those among the estimated 35 seniors aboard the tour bus — were minor, although B.C. Ambulance reports 22 people were treated at the scene and five have critical injuries.

Mounties say further details about the collision are expected to be released later today. (CHNL)

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