PSPS Wind Update

Wind Gusts in Nearly Two Dozen Counties Reached Above 40 MPH; in 15 Counties, Wind Gusts Topped 50 MPH

During Pacific Gas and Electric Company’s (PG&E) Public Safety Power Shutoff (PSPS) last week, wind gusts exceeded 40 mph in 22 counties and topped 50 mph in 15 counties.

The company considers many factors when deciding if a Public Safety Power Shutoff is needed to protect customers and communities, but an important element is how strong the winds will be.

“Our in-house meteorological team and experts from the National Weather Service and other federal agencies were in agreement that this event had the potential for strong winds and a heightened wildfire risk,” said Scott Strenfel, PG&E’s principal meteorologist. “And that’s exactly what happened. The winds arrived and our system sustained considerable damage, yet no fires started as power lines were de-energized.”

During the event, which impacted 738,000 customers, gusts of 77 mph were recorded in Sonoma County and 75 mph in Contra Costa County. So far, the company has confirmed 100-plus incidents of damage or hazards within the PSPS footprint. It is possible that these damages and hazards represented potential sources of wildfire ignition.

Prior to the event, PG&E's meteorologists and fire-weather experts participated in interagency calls with experts from multiple National Weather Service (NWS) offices and the Northern Operations Predictive Services. The experts were aligned that this was a very high fire risk event and had all the ingredients necessary for significant potential fires.

The National Weather Service issued multiple Red Flag Warnings that lasted from Wednesday afternoon until Friday morning that included locations where 2.1 million of PG&E's customers live. The Red Flag Warning encompassed a larger area than the PSPS footprint. Maximum wind gusts exceeded 40 mph in 22 counties impacted by the PSPS event:

• Sonoma County: 77 mph
• Contra Costa County: 75 mph
• Tehama County: 61 mph
• Sierra County: 59 mph
• Butte County: 56 mph
• Napa County: 54 mph
• Santa Cruz County: 54 mph
• Placer County: 53 mph
• Yolo County: 53 mph
• Solano County: 53 mph
• Humboldt County: 52 mph
• Kern County: 51 mph
• Lake County: 51 mph
• Mendocino County: 51 mph
• Santa Barbara County: 50 mph
• Shasta County: 49 mph
• Calaveras County: 49 mph
• Alameda County: 48 mph
• Colusa County: 47 mph
• El Dorado County: 46 mph
• San Luis Obispo County: 46 mph
• Marin County: 40 mph

In his “Weather and Climate Blog,” Cliff Mass, an atmospheric sciences professor at the University of Washington who specializes in weather prediction and modeling, analyzed the weather conditions during the PSPS and talked about the value of “increasingly skillful weather forecasts.”