Heavy rain won't lessen Calif. wildfires – it will fuel them

Click through the images to see the top 20 largest wildfires in California in modern times.



Cal Fire's reliable records date back to 1932, the year of the massive Matilija fire in Ventura County, which burned 220,000 acres. less Click through the images to see the top 20 largest wildfires in California in modern times.



Cal Fire's reliable records date back to 1932, the year of the massive Matilija fire in Ventura County, which burned ... more Photo: Noah Berger/AP Photo: Noah Berger/AP Image 1 of / 28 Caption Close Heavy rain won't lessen Calif. wildfires – it will fuel them 1 / 28 Back to Gallery

California emerged from its five-year drought after heavy winter rains filled reservoirs and turned our golden hills green. But don't be fooled by the emerald hues. The California Department of Forestry and Fire Protection (Cal Fire) expects wildfires to burn just as fiercely as they did during drought years – if not more so.

The Eight-Station Index, a measure of Northern Sierra precipitation that helps determine statewide water levels, has deemed 2017 the wettest year on record at 92.8 inches. With all that rainfall, California's wide open spaces are now covered with lush vegetation.

You'd think that would be good, but firefighters say you'd be wrong. More grass means more fuel for the flames.

When it comes to fires in dry years versus wet years, Cal Fire Capt. Scott McLean says it's a case of "danged if you do, danged if you don't."

The last several years of drought spurred the growth of dry fuel, which enabled fires to spread quickly from one place to the next. While the grass this year is well-hydrated, McLean says the plants won't retain moisture for long.

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"If we get precipitation and then a breeze follows, the grass can dry out in under an hour," he says.

California's five-year drought coupled with a wet year further complicates matters. Over 100 million trees died since 2010 according Cal Fire, and like the grass and brush, felled trees will burn fast and ferociously.

"This will be going on for several years to come," said McLean of the drought's long-lasting impacts. "The winter does not rectify the situation."

Since Jan. 1, wildfires have scorched 5,963 acres of California. During the same interval in 2016, just 530 acres burned. Even then, McLean is hesitant to predict that this season will be more volatile than years past.

"It all depends on the weather," he says.

The unpredictable nature of wildfires means Cal Fire doesn't just fight blazes – it actively works to prevent them through mowing, prescribed burns and inspections. The department oversees 31 million acres across the state, 35,000 of which will be treated this year.

Prevention is an essential ingredient in the ongoing fight against wildfires, which have increasingly begun to burn year-round.

"In California," says McLean, "There is no wildfire season."

Read Michelle Robertson’s latest stories and send her news tips at mrobertson@sfchronicle.com.