At 6:30 a.m., P.d.s.t., during hours of darkness on January 15, 1974 a bus transporting 46 Mexican farm laborers, was traveling northbound on Rannells Boulevard, about 9 miles southwest of Blythe, California. The bus' speed was between 45 and 55 mph--a speed too high to negotiate a limited radius, right-angle turn onto 20th Avenue. A right turn warning sign in combination with a 20-mph advisory speed sign was posted about 350 feet before the curve.
The bus left the roadway, crossed the shoulder, and vaulted into the bottom of a drainage ditch. There was an 18-foot drop from the top ledge of the ditch to the water below. The bus came to rest on its left side, partially submerged. At impact, all seats, except for the last rear, across-the-bus seat and a corner of the driver's seat, were torn from their mountings. Nineteen of the occupants of the bus, including the driver, died in the accident. The cause of each death was drowning.