Idaho Power warned customers of outages during Wednesday storms. Here’s what to know

Tens of thousands of Idaho Power customers Tuesday night received notices that the utility may cut their power as meteorologists predicted high winds and severe thunderstorms could join an already sweltering heat wave, threatening wildfires across Southwest Idaho and eastern Oregon.

A mass notice went out to customers as part of Idaho Power’s public safety power shutoff, or PSPS, initiative. The plan, which Idaho Power presented to Boise City Council last month, calls for preemptive power shutoffs when conditions could spark fires, and it has become more commonplace with utilities across the West as power providers in California, Oregon and Hawaii have been implicated in causing devastating blazes.

Idaho Power spokesperson Brad Bowlin told the Idaho Statesman a second alert was sent to around 55,000 customers Wednesday morning. Customers who received that alert are in areas most likely to see a power shutoff, like the Boise Foothills, southern Ada County and rural communities like Emmett, Homedale and Parma. A map of at-risk areas is available at Idaho Power’s website.

Bowlin said a power shutoff is “kind of a last resort” for extreme weather. This is the first time the utility has issued such a warning in the Treasure Valley. Bowlin said warnings were sent out in Pocatello in 2022 and in Cambridge — a small town between Weiser and New Meadows — earlier this summer, but neither warning resulted in an actual power shutoff.

He said weather conditions make a power shutoff in the Treasure Valley more likely than the previous warning situations. Idaho Power told customers to expect possible interruptions between 5 p.m. and 10 p.m. Wednesday.

The National Weather Service’s Boise office warned of severe thunderstorms and wind gusts up to 70 mph across the region. Storm chances in Boise are around 20% in the afternoon and increase to 50% in the evening, the agency told the Statesman.

Strong winds can cause power lines to break or come in contact with trees, throwing sparks that ignite fires. High temperatures can also cause electrical equipment like transformers to overheat and catch fire. The weather conditions then exacerbate the flames by providing necessary oxygen and drying out surrounding fuels.

Bowlin said Idaho Power has its own team of meteorologists that monitor weather conditions. PSPS notices are sent when the company’s analysts notice a confluence of hot weather, dry fuels, high winds and other fire hazards.

Bowlin said the utility has other ways of trying to mitigate fire risks. He said some lines can be set to “trip,” or interrupt electrical supply, more easily during high winds. Lines can also be configured so they don’t try to re-energize after they’re tripped, reducing the likelihood of an ignition. It has used those methods in the past when fire risks are high, but Bowlin said increased fire risk from a changing climate and an influx of residents, as well as improved power transmission technology, make a public safety shutoff another option.

“We know some folks have been a little bit caught off-guard to get these notifications,” Bowlin said. “We’re doing our best to deliver electricity safely.”

An Idaho Power transformer blew Monday evening, sparking a grass fire in the Warm Springs Mesa neighborhood near Harris Ranch. More than 3,000 customers lost power for about 90 minutes. The same group of customers experienced about a 50-minute outage Wednesday. The latest outage was caused by an excavator not owned by Idaho Power hitting a power line, Bowlin said.

Idaho Power has been accused of causing large-scale wildfires in the past, including Oregon fires in 2014 and 2015 — for which it paid $1.5 million to settle the allegations — and a 2008 fire in southeast Boise that killed a Boise State University professor.

Reporter Sally Krutzig contributed.