California Highway Patrol spokesman Mario Lopez said the number of eight confirmed deaths was expected to rise because the coroner was just starting to remove bodies from the mangled vehicle and also remove the bodies of those who were ejected, which were covered by yellow blankets.
"It appears speed was a factor in this collision," Lopez said. Investigators will determine if mechanical failure or driver error was to blame, he said. The driver survived.
Authorities had not yet obtained the passenger list from inside the bus, Lopez said.
The accident occurred around 6:30 p.m. about 80 miles east of Los Angeles and left State Route 38 littered with debris, the bus sideways across the two lanes and its front end crushed.
The bus was returning to Tijuana, Mexico, Lopez said. It rear-ended a Saturn sedan and hit a Ford pickup, he said. One person in the pickup was injured. The fate of the passengers in the car was not clear, but at least two people were in it, Lopez said.
California Department of Transportation spokeswoman Michelle Profant said the scene was shocking.
"It's really a mess up there with body parts," she said.
The bus driver told investigators the bus suffered brake problems as it headed down the mountain, Lopez said.
Lettering on the bus indicated that it was operated by Scapadas Magicas LLC, a company based in National City, Calif. Federal transportation records show that the company is licensed to carry passengers for interstate travel and that it had no crashes in the past two years.
A call to the company was not immediately returned.
Jordi Garcia, a manager for InterBus Tours, said his company ran Sunday's trip. He told U-T San Diego that 38 people departed Tijuana at 5 a.m. for a day of skiing at Big Bear.
"The information that we have is that the bus' brakes failed and the accident occurred," he said.
Route 38 runs through the San Bernardino National Forest and leads to Big Bear. The accident occurred as the bus was headed south and leaving the forest.
Patients were taken to several area hospitals with injuries ranging from minor to life-threatening.
Arrowhead Regional Medical Center on Monday morning had two women in critical condition and two other patients in stable condition. Two other women were discharged early Monday. Redlands Community Hospital had one patient in critical condition and five other patients ranging from minor to moderate condition with injuries ranging from cuts to broken bones, spokeswoman Nikyah Thomas-Pfeiffer said. Loma Linda Medical Center had a man and a girl under age 18 in critical condition, a man in serious condition, and a woman and a girl under 18 in fair condition, spokesman Herbert Atienza said.
The California crash comes less than a day after a bus carrying 42 high school students and their chaperones slammed into an overpass in Boston. Massachusetts state police said 35 people were injured and that the driver had directed the bus onto a road with a height limit.
Associated Press writers Andrew Dalton in Los Angeles, and Amanda Kwan and Bob Seavey in Phoenix contributed to this report.