Powerhouse Number Two - Turbine driven power generation plant of DWP.

March 13, 1928, 12:03 a.m: Five minutes after the collapse, having traveled 1-1/2 miles (2.4 km) at an average speed of 18 mph (29 km/h), the now-120-foot-high (37 m) flood wave destroys the heavy concrete Powerhouse No. 2 — leaving only two turbines — and claims the lives of 64 of the 67 workmen and their family members who lived nearby. 

The canyon is particularly narrow in this area and switches back and forth with steep faces on either side.  The powerhouse consisted of two very large pipes running down a severe slope to the riverbed below through which water from the elevated reservoir would pass and rapidly spin two large turbines and generate electricity in doing so.  By regulating the flow of water, the rate of electricity generation could be controlled and optimized using gravity and some early twentieth century heavy machinery.  Less than 100 workers were needed to oversee and maintain the system.

Lyman Curtis, who helped building roads during and after the dam's construction, and his wife Lillian notice a strange mist in the air and conclude the dam has collapsed and they have only minutes to escape. Lillian, her son Danny and the family dog head for high ground while husband Lyman goes back into their house to gather daughters Marjorie and Mazie. Only Lillian and Danny survive. 

Ray Rising, a utility man from the powerhouse, also is awakened and faces a 10-story-high wall of water. Swept into the floodwaters, he manages to climb onto a floating rooftop, which transports him to safety. He is the only other survivor at this power plant.  In his words when interviewed after the tragedy

“We were all asleep in our wood-framed home in the small canyon just above the power house. I hear a roaring like a cyclone. The water was so high we couldn't get out the front door. The house disintegrated. In the darkness I became tangled with an oak tree, fought clear and swam to the surface. I was wrapped with electrical wires and held by the only power pole in the canyon. I grabbed the roof of another house, jumping off when it floated to the hillside. I was stripped of clothing but scrambled up the razorback of a hillside.”