Threat of wildfire can shut down power

Imagine waking up in Sisters to no power. Not from a local failure in your home or business, or a transformer in the neighborhood failing, but from a decision made miles away to shut the power to an entire community. It could well happen, depending on the severity of weather conditions, especially in wildfire season.

It was just last August when a loaded gasoline tanker truck struck a main pole on Highway 126 in Cloverdale, causing a widespread power outage in Sisters. Power was off for hours and internet service took multiple days to restore in some areas. Most merchants in town lost the ability to make sales, resorting to cash only or closing early. ATMs could not be accessed as, like stores, they rely on an internet connection to complete transactions.

Power companies, several of whom have been hard hit by lawsuits, are being far more proactive in turning off the juice before a wildfire takes hold. Power lines and overheated transformers that often explode in such fires can exacerbate a fire.

What's more is the enormous potential cost to power providers' infrastructure, investments that can run into the billions of dollars.

Their answer to avoid costly litigation and being a partner in fighting wildfires is a public safety power shutoff (PSPS). This is a safety measure designed to help protect communities in high fire-risk areas by proactively shutting off electricity during extreme and dangerous weather conditions that might cause the electricity system to spark wildfires.

While utilities often restore power for customers even before a winter storm has ended, during extreme winds in the summer, utilities will need to inspect power lines for damage after winds or fire have passed. It may take longer to fully restore power safely in the summer.

Just how long? That is elusive and depends on the individual event. But it could be days.

The Nugget asked Brent ten Pas, vice president of member and public relations at Central Electric Cooperative, the area's power supplier, how Sisters and Camp Sherman fit into the overall plan.

"The Sisters area, including Tollgate, Black Butte Ranch, and Camp Sherman, would most likely be subject to a public safety power shutoff before the areas west of Redmond, as the former is categorized as a 'Very High' wildfire risk area, and the latter a 'High-Risk' area.

"Should CEC execute a PSPS for the Sisters area, we would make every effort to keep the downtown core energized while the south, west, and north regions would be de-energized," he said. "Once the PSPS event has passed, CEC personnel must visually inspect every inch of the overhead transmission and distribution lines to ensure no foreign object has come into contact before reenergizing the lines."

Photo by Bill Bartlett

Electric transmission station in Redmond that redistributes power for Sisters and Camp Sherman.

He lined out the protocol: "CEC personnel would begin patrolling the transmission lines west of Redmond, serving Sisters, Tollgate, Black Butte Ranch, and Camp Sherman. In the best-case scenario, after visual inspections from west of Redmond to the Sisters area confirm that no foreign object has come into contact with the powerline or that any other damage has occurred, CEC could restore power in the Sisters and Tollgate areas within approximately six hours.

"Extending beyond Tollgate to Black Butte Ranch would require approximately an hour to inspect the transmission line before CEC would restore power, provided there are no immediate threats or damage. Camp Sherman poses the most significant challenge due to its terrain and the overhead distribution powerlines running through the forest. Three crews would need approximately six hours to inspect every inch of the three separate powerlines."

The Nugget asked if CEC could be more specific regarding "sustained high winds and low humidity." ten Pas replied: "The National Weather Service issues various warnings when dry fuels and weather conditions support extreme fire danger. A Fire Weather Watch is issued up to 72 hours before conditions are expected to occur, and a red flag warning is issued within the next 24 hours should those conditions exist. A high wind watch is issued 12-36 hours in advance when sustained winds of 40 mph or higher for one hour or more, or wind gusts of 58 mph or higher for any duration."

High wind warnings are issued when sustained winds of 40 miles per hour or higher for one hour or more, or wind gusts of 58 mph or higher for any duration.

"The NWS could issue a red flag warning for the Sisters area when the relative humidity is 15 percent or less, and the sustained wind speeds are 10 mph or greater.

"These factors alone, however, do not necessarily warrant that CEC would execute a PSPS, as there are many variable factors to consider," he added.

Other criteria CEC would consider besides the NWS' red flag warnings are real-time reports from CEC personnel dispatched to high-risk areas monitoring wind speeds, debris blowing, or observing any immediate threats to its electric infrastructure or public safety.

"Also, pre-existing or new wildfire starts could require PSPS to aid in firefighting efforts or provide safe conditions for first responders," ten Pas said.