(ABC News) -- Nine people are dead and more than 20 are injured after a charter bus crashed on an icy highway in Oregon, according to Oregon State Police.
Police have not yet indicated what caused the crash, but images from highway I-84 show icy roads. The bus crashed through a guard rail at around 10:30 a.m. today and slid several hundred feet down an embankment, police said.
Emergency responders trained in rope rescues were on-scene helping bring people up from where the bus rolled back onto the highway, police said.
The crash happened about 10 miles east of Pendleton, Ore., in the Blue Mountains.
Investigators are still trying to determine whether the crash was weather-related, State Police spokesman Lt. Greg Hastings said.
"We'll have to move through our investigation throughout the day to try to determine what exactly were the contributing factors," he said.
The bus driver survived the crash but investigators had not be able to speak to the person early this evening because of the severity of the driver's injuries, officials said.
The Pendleton Fire Department told ABC affiliate KATU-TV in Portland that 39 people were taken to hospitals.
St. Anthony Hospital in Pendleton treated 26 people from the accident, including some who were treated and then transported to other medical facilities, hospital spokesman Larry Blanc told The Associated Press.
Officials are not yet releasing the bus company, but said the bus was enroute on a return trip from Las Vegas, Nevada to Vancouver, British Columbia.