Thunderstorms developing Saturday in the Sierra Nevada could aid firefighters battling the King fire, which had grown to nearly 82,000 acres by 7 p.m., but fire planners are keeping close watch on the suddenly shifting winds that accompany such weather.
Thunderstorms were developing along the crest from Sierra-Tahoe to Kirkwood, said Craig Shoemaker, a National Weather Service forecaster. What that means, he said, depends on whether the systems hold up. About a quarter-inch of rain could fall bringing isolated gusts of 30 to 40 mph.
The wind “is a main issue,” however, not just for its strength but its direction, Shoemaker said. Afternoon winds in the Sierra are normally westerly but could shift east with the thunderstorm activity and affect where the fire burns.
“A sudden shift from westerly to easterly is possibly the biggest concern,” Shoemaker said.
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But humid conditions and the possibility of showers after midnight could be good news for those on the fire lines.
“The winds are a concern but a positive is the higher relative humidity,” Shoemaker said, adding that relative humidity could be anywhere from 60 to 80 percent with night time temperatures of 55 to 60 degrees over the fire area.
“The rain would be nice, but thunderstorms create their own problems for us. The winds can be very erratic,” said Lynne Tolmachoff, a spokeswoman for the California Department of Forestry and Fire Protection. The erratic winds can quickly change a fire's direction making a dangerous environment even more so for firefighters.
Thunderstorms had yet to materialize in the fire zone, but “we'll be very careful to pay attention. We’ll watch it very carefully,” Tolmachoff said.
About 5,000 firefighters from California and across the nation are battling the blaze, which as of 7 p.m. Saturday had blackened 81,944 acres in El Dorado and Placer counties. The fire continues burning a path northward toward Hell Hole Reservoir and had grown so large that fire officials have opened a second command post in Foresthill.
Dense smoke had grounded air tankers and other firefighting aircraft on Friday, but retardant-laden tankers were able to return to the skies Saturday supporting the hand crews who chopped away on the forest floor.