LAX88FA163

During inclement wx on an EMS flight with a nurse and patient onboard, the helicopter collided with power lines which were suspended 36 feet above a road. Control was lost and the helicopter collided with a retaining wall, clipped the tops off several trees and plunged into a 70-foot deep ravine. The main wreckage came to rest about 220 feet from the initial point of impact. The sole survivor was the patient; he had been strapped onto a full body board. Despite the pilot's extensive military & civilian flight experience & concern for flight safety, the overriding life-saving mission coupled with job pressures contributed to him delaying his decision to turn around. Also contributing was the dispatcher's/management's failure to readily provide the pilot with alternate destination instructions upon the closure of the primary destination's trauma center.