When tornado-like winds tore through parts of Oregon in late May, the potential for widespread power outages was a real concern for BPA’s line crews and dispatchers, as well as the weather forecasters who had predicted the unusually destructive weather events.
“Our initial reactions when we found the towers was a moment of great suspense. It was dark, and we didn’t know at first how many towers were down,” said Nate Seabury, Redmond District Manager. “There is always that moment when you find yourself in hot water, when you want to know just how hot the water is.”
For Seabury, the experience and uncertainty of his transmission line crew as they responded to an outage that day was further exacerbated by the ongoing threat of COVID-19. Remarkably, thanks to crews’ quick responses and the resiliency of BPA’s grid, there were no significant regional outages as a result of damage to the agency’s grid.
The storm first revealed its potential to BPA’s weather forecasters the day before, when BPA’s Weather and Streamflow Forecasting issued a Transmission Weather Alert for the possibility of widespread thunderstorms.
BPA has long used weather forecasters as a way to better understand water supply trends in the Columbia River Basin. That water is the fuel of the federal hydropower system that forms the backbone of the Northwest’s electrical grid and power supply. Those forecasts inform decisions on how and when to move water through the system of federal dams to ensure BPA can meet the demand for power in the region as well as support its environmental mission to fish and wildlife.
In recent years, the forecasters have extended their work to advise on the potential for storms or other environmental conditions that might impact BPA’s work or its mission.
These Transmission Weather Alerts help district crews position themselves and their equipment to respond to emergency outages. In some instances with severe storms, district managers will pause maintenance and other work to improve that crew’s response posture.
As anticipated, unusually widespread and severe thunderstorms developed May 30, including a few supercells that produced two-inch diameter hail. Winds topped 85 mph, and at least one microburst event tore through the area. Microbursts are highly localized weather events with very strong winds and destructive attributes similar to a tornado.
“This is certainly one of the most severe storms we have seen in several years,” said Erik Pytlak, the manager of BPA’s Weather and Streamflow Forecasting group. “It looks more like something you’d see in Iowa or Oklahoma rather than Eastern Oregon and Washington.”
Throughout the day, BPA’s Transmission Dispatch managed multiple events across the agency’s service territory. Lightning strikes resulted in outages and even a few fires in the Tri-Cities area. At 3 p.m., a severe thunderstorm passed over power lines about 40 miles southeast of The Dalles. Dispatch started receiving alarms from various substations in the area, indicating lightning strikes and outages.
At 4:45 p.m., dispatch received a call that a local resident near Metolius, Oregon, reported he could see visible damage to a transmission line near his house. The Transmission Line Maintenance crew out of Redmond was mobilized.
The severe storm that had passed over the lines unleashed a microburst. Steel structures meant to withstand ice, strong winds and earthquakes buckled under the intensity of straight line winds exceeding hurricane and tornadic wind speed thresholds. The estimated 115 mph winds crumpled one steel tower and damaged another.
While the storms headed east, dumping rains that resulted in localized flooding, BPA’s crews were already working to mitigate the outage and assess the damage.
The storm came just at BPA’s Transmission crews were preparing to reopen field districts that had been closed due to the COVID-19 pandemic.
“We were just getting back to work with many other priority tasks when we got the call from dispatch,” said Seabury, referring to the TLM Redmond crew. “It is just this kind of emergency that keeps a sharp line crew like we have in Redmond even better prepared for other emergencies that come to our doorstep. It makes our training and readiness relevant and reminds me of a quote from the British philosopher G.K. Chesterton, ‘I believe in getting into hot water; it keeps you clean.’”
The Redmond TLM crews were joined by crews from Alvey and Ross districts, as well as the specialized Live Line Crew.
The incredible efforts of the line crews, dispatchers, weather forecasters, and everyone else involved turned a severe weather event into an almost unremarkable day for the millions of people relying on the power transmitted across BPA’s lines.