[3] A brief grounding and misconfigured relay then effected the deficiency, and protective devices separated large segments of the grid faster than operators could react.
[2]: 31 [5] President Bill Clinton directed the United States Department of Energy to investigate the reasons for the widespread power outage and whether it could have been prevented.
[6] Bonneville Power Administration had failed to adequately clear their right-of-way, and multiple lines arced to nearby vegetation.
Five minutes later, at 3:47 p.m., the 230 kV Ross–Lexington line (also owned by Bonneville Power Administration) flashed and grounded to a tree near Vancouver, Washington, across the Columbia River from the Portland/Hillsboro area.
The outage stretched from Canada to New Mexico and knocked out power to 4 million customers amid a triple-digit heat wave.