One of six charter buses carrying members of the University of Washington marching band to a football showdown at Washington State University rolled onto its side Thursday on Interstate 90, the Washington State Patrol said.

No serious injuries had been reported from the accident that was called in to authorities at 5:26 p.m., Trooper John Bryant told the Seattle Times. Forty to 45 students were treated for injuries that were not serious or life-threatening, Bryant said. The bus carried 56 people, he added.

Troopers, paramedics and deputies from the Grant County Sheriff's Office responded to the accident, he said.

The accident took place on eastbound I-90 at mile post 146, about 3 miles west of George in central Washington, Bryant said.

Road conditions were extremely slippery and icy in spots, the trooper told the Times.

The charter buses were headed to the Apple Cup, which is scheduled for Friday, in Pullman.

School officials were attempting to load students and equipment from the crashed bus onto the five other charter buses traveling together to continue the trip to Pullman, Bryant said.

Update, 9:40 p.m.: This story has been updated and corrected with new information from the Washington State Patrol regarding the number of students injured and number of buses in the marching band caravan.

-- The Associated Press