On August 10, 1996, during a period of high temperatures and high demand for electricity, a major transmission line failure knocked out power to 4 million people in eight West Coast states. The impacts were immediate and, in areas such as the San Francisco Bay area, they lasted for hours. For the most part, the major power outage was just a major inconvenience. Planes continued to land and take off at the city’s airport, but the electrically operated jetways were grounded. Traffic lights winked out, and gridlocks ensued. Chefs at the famous Hays Street Grill in San Francisco set up barbecues in the alley in back of the restaurant, and elsewhere there were sudden markdowns of refrigerated foods.

The cause of the chaos? At 3:42 p.m., a power line sagged into filbert trees near Hillsboro, Oregon, just southwest of Portland. It was the fourth power line in Oregon to fail in less than two hours. Five minutes later, at 3:47 p.m., a line shorted out in Vancouver, Washington, across the Columbia River from the Portland/Hillsboro area. At 3:48 p.m., the 13 turbines at McNary Dam, on the Columbia about 190 miles upstream from Portland, quit operating. The combination of the power outages and the temporary loss of McNary triggered a cascade of power outages as far away as southern California.

Without McNary, there wasn't enough voltage support to maintain transmission of electricity on the Pacific Northwest-Pacific Southwest Intertie, the grid of high-voltage power lines that links 14 western states and parts of Mexico and Canada. It was the second major West Coast outage in less than a month and a half. On July 2, a series of problems cut off power to 2 million customers. Blame for the outages fell mainly on maintenance of power lines, and the impact of increasing energy industry competition, which forced cost-saving cutbacks in areas like power line maintenance.

Randy Hardy, then administrator of the Bonneville Power Administration, which operates the lines that failed, said after the August outage: “We are quite chastened by this incident, and we are going to be quite cautious about how we proceed in these things because we’re talking about basic public health and safety.” Hardy promised that Bonneville would improve maintenance and communications with its utility customers in the hope of avoiding similar incidents in the future.

But the matter is more complicated than filbert trees, the inconvenience of a blackout, and power line maintenance. The August outage prompted serious hand-wringing over the future of some Columbia River dams, particularly John Day. In a report to the Columbia-Snake River Irrigators Association and the Eastern Oregon Irrigators Association in December 1996, water management consultant and retired Corps of Engineers employee Russell L. George wrote that the blackout demonstrated the Intertie was very sensitive to generation levels at the lower Columbia River dams, particularly John Day Dam where a permanent drawdown to aid salmon migration and passage was favored by salmon and steelhead advocates. George wrote that such a drawdown would reduce the hydropower output at the dam and, as a result, reduce the operating limits on the AC and DC Intertie lines.

In response to concern from environmental groups, fish and wildlife agencies and tribes, the Corps, which operates John Day Dam, had studied the possibility of permanently lowering 77-mile Lake Umatilla behind the dam to reduce its size and create spawning habitat for fall Chinook salmon in its upper end. While some advocates supported a permanent drawdown at John Day because of the potential benefit for fish, such a drawdown would greatly reduce or possibly eliminate power generation at the dam. And while it is true that replacement generation could be built, nonetheless the fast-growing filbert trees, the McNary Dam impact and the blackouts of 1996 provided new insights for the debate about whether to draw down the reservoir. Ultimately, the Corps decided against a deep drawdown at John Day, preferring instead a periodic drawdown of just several feet during the salmon migration period.