The northbound truck reportedly lost its brakes around the 200 block of Ramona Road at 10:45 a.m. Thursday, Aug. 9, and plunged several hundred feet down into a wooded ravine off the north edge of the road, said officers from the California Highway Patrol and firefighters from the Woodside Fire Protection District.
The San Mateo County Hazardous Materials Team also responded to the incident after diesel fuel was found to have leaked out of the truck and contaminated the ground in a dry creek bed where it came to rest.
The driver was taken to the hospital after climbing up and out of the ravine under his own power, said Woodside Fire's Chief Armando Muela. The slope was so severe that firefighters had to resort to ropes and climbing gear to rappel down to where the truck came to rest.
On its way over the edge, the runaway truck pushed before it two unoccupied vehicles — a small pick-up truck and a sports utility vehicle. Firefighters said they did not know whether the truck was loaded when it crashed, but found the bed to be empty. The CHP estimated the truck's empty weight at 30,000 pounds to 35,000 pounds.
Firefighters pointed to a 20-foot to 30-foot scar of what appeared to be freshly plowed earth along an embankment just before the point where the truck left the road. The driver may have tried to use the embankment in an effort to scrub off speed.
As the truck rolled down into the ravine, diesel fuel spilled from its twin 48-gallon tanks, with one tank completely ruptured and the other punctured and leaking, a CHP officer said at the scene.
The soil contaminated by the diesel fuel will be dug up, put into canisters and hauled off to a hazardous materials dump by the company that owns the truck, said Brian Molver, the hazardous materials duty officer that day and a member of San Mateo County's Office of Emergency Services. The step is intended, in part, to prevent the fuel from contaminating Los Trancos Creek, Mr. Molver said.
Tow trucks gathered at the scene, including at least one with a boom that could handle a weight of 100,000 pounds, a driver said. In mid-afternoon the wreckage, a functioning dump truck earlier that day but now barely recognizable, was hauled up and out of the ravine.