The bus' driver lost control about 10:30 a.m. along a rural part of Oregon's Interstate 84 near Pendleton. A steel guardrail did little to keep the tour bus -- and its roughly 40 passengers -- from going over an embankment and dropping 85 feet, reports correspondent Lee Cowan.
This stretch of I-84 (a major east-west highway that follows the Columbia River Gorge) is so notorious that state transportation officials have published a specific advisory warning of its dangers.
Lt. Gregg Hastings of Oregon State Patrol said the bus crashed along the west end of the Blue Mountains, and west of an area called Deadman Pass. The area is well known locally for its hazards, and the state transportation department advises truck drivers that "some of the most changeable and severe weather conditions in the Northwest" can lead to slick conditions and poor visibility. Drivers are urged to use "extreme caution and defensive driving techniques," and warned that snow and black ice are common in the fall through the spring.
"We're not blaming road conditions," said Lt. Hastings. "We know that there was some snow and ice on area roads, but the investigation is just beginning."
The driver of the bus was injured, but survived. That testimony -- more than anyone's -- will be able to tell investigators just what went wrong.
The bus crashed near the start of a 7-mile section of road that winds down a hill. The weather Sunday was hardly optimal - and made getting down to the injured and dying a time-consuming process, officials said. Dozens of rescuers followed a black scar down the side of the ravine to find the bus at the bottom -- resting upright, but with significant damage.
"There was snow on the ground which made pretty treacherous, so we used a haul system to get the patients or some of the patients from the crash site . . . back up to the highway so they could be transported to medical facilities," said Jim Voelz of the La Grande Rural Fire Department.
The most seriously hurt were air-lifted to hospitals as far away as Portland and Boise, Idaho.
The East Oregonian said it spoke with two South Korean passengers, ages 16 and 17. Both said through a translator that they were seated near the rear of the bus when it swerved a few times, hit the guardrail and flipped. They described breaking glass and seeing passengers pinned by their seats as the bus slid down the hill. Both said that they feared for their lives.
The paper said that the teens, one of whom injured a knee and the other suffered a broken collarbone, were staying at a hotel arranged by the Red Cross.
The bus had been carrying about 40 people. St. Anthony Hospital in Pendleton treated 26 of them, said hospital spokesman Larry Blanc. Five of those treated at St. Anthony were transported to other facilities.
Blanc did not elaborate on the nature of the injuries but told the Oregonian that the hospital brought in additional staff to handle the rush of patients and did a lot of X-ray imaging.
The bus owned by Mi Joo Travel was headed, state police say, from Las Vegas to Vancouver, Canada.
A woman who answered the phone at a listing for the Vancouver-based company confirmed with The Associated Press that it owned the bus and said it was on a tour of the Western U.S. She declined to give her name.
A bus safety website run by the U.S. Department of Transportation said Mi Joo Tour & Travel has six buses, none of which have been involved in any accidents in at least the past two years.
The bus crash was the second fatal accident in Oregon on Sunday morning. A 69-year-old man died in a rollover accident on I-84, about 30 miles west of where the bus accident took place.
Sunday's Oregon bus crash comes more than two months after another chartered tour bus veered off a highway in October in northern Arizona, killing the driver and injuring dozens of passengers who were mostly tourists from Asia and Europe. Authorities say the driver likely had a medical episode.
A spokesman for the American Bus Association said buses carry more than 700 million passengers a year in the United States.
"The industry as a whole is a very safe industry," said Dan Ronan of the Washington, D.C.,-based group. "There are only a handful of accidents every year. Comparatively speaking, we're the safest form of surface transportation."