San Diego County’s highest possible wildfire alert has been issued for Thursday as forecasters warn of strengthening Santa Ana winds combined with single digit humidity levels.

“We expect things to get worse before they get better,” said Alex Tardy, warning coordination meteorologist with the National Weather Service.

The Santa Ana Wildfire Threat Index map uses four colors to display increasing levels of severity — from yellow to orange to red to purple. Thursday is projected to be purple, the highest level, which has never been issued in the county since the program began in 2014.

“It takes low humidity, it takes high wind speed, it takes dry fuels so the vegetation is ready to burn,” Tardy said. “We have seen big, large uncontrollable fires in these conditions historically when you match it all together. And that’s what puts us in the purple.”

The extreme purple warning means “fires could have explosive growth, burn very intensely and be uncontrollable."



“Now when things really turn the corner and get a little scary is Wednesday night and Thursday morning,” Tardy said. “And really all day Thursday is when we could see the potential for those 80 to 100 mile per hour winds. One-zero-zero. 100-mile per hour winds in the mountains.”

Easterly sustained winds of 20-45 mph are expected along the coast and inland valleys, with gusts exceeding 90 mph over the higher terrain.

Tardy emphasized wind conditions will vary greatly.

“Our mountains and our terrain is rolly, it has gaps, it has holes, it has peaks,” Tardy explained. "And so the winds follow that. So if you’re in a wind prone area that means you’re exposed to those easterly, northeasterly winds. If you’re protected by a mountain or building or hill or something like that you may not see as much wind.”

'Extreme' Fire Warning Issued For Thursday In San Diego County Your browser does not support inline frames or is currently configured not to display inline frames. Content can be viewed at actual source page: https://www.youtube.com/embed/jIrtp8foCCM

Humidity levels on Thursday are expected to dip to the 5-15 percent range.

“It’s a very critical situation,” Tardy said. “It’s a situation where everyone has to be involved and paying attention to prevent the fires because one cigarette, one spark, one backfiring vehicle, one piece of equipment, one power line could affect millions of people.”

Even without flames, winds could cause damage, Tardy warned.

“When you start talking over 60 miles per hour, over 70 miles per hour — easily that could be any tree, any loose object, any roof could be damaged," he said.

Tardy said San Diego County is experiencing one of its driest starts to the rainy season ever recorded, with just .02 inches measured at Lindbergh Field since Oct. 1.



How SDG&E Responds To Threat Of Wildfire GUEST: Allison Torres, communications manager, SDG&E

Transcript for audioclip 37777

San Diego County’s highest possible wildfire alert has been issued for Thursday as forecasters warn of strengthening Santa Ana winds combined with single digit humidity levels.

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