(Image source: East Oregonian )   BY CHRISTINE SLUSSER   At least nine people have died after a bus slid on an icy highway and crashed in Pendleton, Oregon. WHDH has more. WHDH : “The bus lost control on a patch of ice and crashed through guardrail. it fell several hundred feet down an embankment. 20 people were injured in in the wreck. rescue workers had to use rope to pull survivors up from the crash site.” Authorities haven’t officially announced the cause of the crash, but images from the wreckage show that the highway was icy. WKYC reports. WKYC : “The bus driver survived but investigators haven't been able to talk to him yet because he is still in the hospital.” And WBBH has more chilling details. WBBH : “It appeared that most of the patients had actually been ejected from the bus as the bus went down the cliff.” “The bus was returning to Vancouver, British Columbia from a trip to Las Vegas.” The cause of the crash remains under investigation.