Utility wildfire experts told WECC last week that another expected year of hot, dry weather will increase the danger of major fires in California, Arizona and the Pacific Northwest that could threaten the electric grid during the West’s annual fire season.

“If you look at any of the indices across the Southwest, certainly the potential is there for some very large and frequent fires this year,” said Wade Ward, fire mitigation specialist with Arizona Public Service (APS).

In Arizona, an extended drought has produced hazardous conditions in the state’s vast ponderosa pine forests atop the Colorado Plateau, the site of massive wildfires in prior years, including the state’s largest wildland blaze, the 538,000-acre Wallow Fire in 2011 and the 469,000-acre Rodeo-Chediski Fire in 2002.

Trees on the Mogollon Rim, which marks the southern edge of the plateau, are so stressed by drought that they are bursting into flames during controlled burns by the U.S. Forest Service intended to reduce ground fuels near power lines, Ward said.

“These drought-stressed trees are not acting and reacting the same way to prescribed fire as they did in years past,” Ward said. “They’re so drought-stressed that in what is typically moderate fire activity or even low fire activity … these trees are torching out, and we’re ending up with miles of hazard trees right outside of our right of way.”

The utility has undertaken measures to remove the dead trees to prevent them from falling on lines, he said.

WECC’s webinars on Wednesday and Thursday focused on a key part of WECC’s reliability efforts, with presenters from APS, Southern California Edison (SCE), Pacific Gas and Electric, San Diego Gas & Electric, the Los Angeles Department of Water and Power and the Bonneville Power Administration (BPA). The utilities outlined risk factors and discussed strategies to prevent fires.

APS developed an index that shows areas at highest risk for wildfires as a “big red stripe” crossing the state from the Grand Canyon in the northwest to the New Mexico border in the southeast, Ward said. Major transmission lines traverse the red zone.

“Our transmission system of over 5,000 miles and our distribution of over 29,000 miles pretty much can’t go anywhere in this state without fire impacting our system,” Ward said. “Just in the last week, we’ve had three large fires that either have impacted or are potentially impacting our system right now, so the fire season here has started off really, really fast.”

California

Utilities in California also are facing daunting fire conditions this year after a second dry winter.

Gov. Gavin Newsom declared a drought emergency for 41 of the state’s 58 counties after unseasonably warm conditions in April and May caused the already thin snowpack to melt faster than usual. The snowpack in the Sierra Nevada and other mountain ranges supplies the state with water during its dry season, which generally lasts from May to October.

“With the reality of climate change abundantly clear … we’re taking urgent action to address acute water supply shortfalls in Northern and Central California,” Newsom said in a statement May 10.

With warmer, dryer conditions, a big concern is that this year’s fire season could equal or exceed last year’s record-breaking season. Five of the six largest fires in state history occurred in summer and fall of 2020.

By the end of the year, “nearly 10,000 fires had burned over 4.2 million acres, more than 4% of the state’s roughly 100 million acres of land,” the California Department of Forestry and Fire Protection (Cal Fire) said. “California’s August Complex fire [in Northern California] has been described as the first ‘gigafire,’ as the area burned exceeded 1 million acres. The fire crossed seven counties and has been described as being larger than the state of Rhode Island.”

Southern California is in jeopardy, too.

Raj Roy, principal manager of wildfire resiliency oversight at SCE, told the WECC audience that more than a quarter of the company’s territory lies within high-risk fire areas.

Wildfires last year threatened transmission lines and, in some circumstances, resulted in lines being shut down. During a severe heat wave in September, wildfires raging in Central and Southern California took 1,600 MW of transmission capacity out of service, forcing CAISO to declare a Stage 2 energy emergency. (See CAISO Avoids Blackouts amid Brutal Heat, Fires.)

“Last year was a record year … and it’s showing the effects of climate change,” Roy said. “Talking to our fire scientists, we actually have more drier fuels at this time of year. That’s something we have to prepare for.”

Pacific Northwest

BPA has recognized the growing threat of wildfires in the Pacific Northwest and adopted public-safety power shutoff (PSPS) plans like those used by California’s investor-owned utilities.

“We have been noticing our fire seasons getting longer, and the longer those fire seasons get, the greater the chance that you’re going to have a ‘red flag’ situation, [with] very dangerously low humidity, very dry fuels, maybe even lightning — combined with a high-wind event,” Erik Pytlak, BPA’s supervisory meteorologist, said in April. (See With Wildfire Season Looming, BPA Prepares Shutoff Plan.)

The normally lush Pacific Northwest experienced wildfires in recent years more like the wildfires usually seen in drier regions to the south. One conflagration engulfed large, heavily forested areas of Western Oregon last September, prompting widespread evacuations and blanketing the region in heavy smoke for more than a week. At least 11 deaths have been attributed to the event.

A lawsuit blames Pacific Power, the state’s second largest utility, for one of the fires, although the cause is still under investigation. (See PacifiCorp Faces Class Action over Wildfire Response.)

Oregon’s largest electricity provider, Portland General Electric, implemented the state’s first-ever PSPS in the Mount Hood area just before the fires flared up over the Labor Day weekend. (See High Fire Danger Prompts First Oregon PSPS Event.)

To prepare its PSPS plan, BPA met with SCE and other California utilities to learn from them, said James V. Hillegas-Elting, project manager of BPA’s effort, in Wednesday’s webinar. Like those utilities, BPA prepared its plan because of the “critical need for asset protection [and] for public safety protection in the midst of these evolving environmental conditions,” Hellegas-Elting said.