A long-duration heat wave will hit California in early August, just as the state enters what is historically the peak of its wildfire season.
Rapid drying of the landscape is expected amid the hot weather. Vegetation will be more flammable than any point so far this year, with near-record levels of energy available for any fire that does break out.
The National Weather Service has not issued fire weather watches or red flag warnings anywhere in California due to a lack of wind, but advises people to avoid activities that may spark a fire.
Human-caused wildfires are nearly 10 times more likely than lightning-sparked fires and consume significantly more acres. No lightning is in the forecast in California for the next week.
“If a fire gets going, especially further towards the interior, including like the mountains … you could see that plume-dominated behavior with those taller smoke clouds that we associate with summertime fires,” said Bryan Lewis, a meteorologist at the weather service office in Los Angeles.
Above-normal temperatures are predicted through mid-August, and elevated fire danger will persist. No major wind or lightning events are expected for the foreseeable future, so fire behavior will mainly be driven by daily weather cycles, with the hottest weather and most active fire spread in the afternoon and evening, and cooler, quieter periods from night through morning.
California’s fire season to this point has been quiet relative to neighboring states.
About 210,000 acres had burned statewide this year through July 28. That was about two-thirds of the five-year average, according to Cal Fire.
A blaze engulfs trees on the Summit Fire in Llano (Los Angeles County) on July 10. About 210,000 acres have burned statewide this year through Wednesday. That’s about two-thirds of the five-year average, according to Cal Fire. (Ethan Swope/Associated Press)
Meanwhile, Oregon is on track for its worst fire season in the modern era. Blazes there have consumed more than 1.8 million acres this year, which is just shy of the record for a single season, according to Salem’s Statesman Journal. Explosive early summer fires in Utah torched more land than the past five years combined. Washington, Arizona and Colorado have all contended with large fires and smoky skies.
The reason for California’s relative good fortune so far is generally threefold:
More than 71% of the West is experiencing drought, compared with just 6% of California, according to the U.S. Drought Monitor. The relationship between drought and fire is complex, but drier landscapes generally increase the potential for large wildfires.
Moderate drought (brown) or worse plagued 71% of the West as of last Thursday, according to the U.S. Drought Monitor. Abnormally dry conditions (yellow) cover much of California, but less than 6% of the state was experiencing official drought. (Baron/Lynx)
July temperatures were also right on par with normal across most of California, particularly in the northern half of the state. This weekend’s heat wave will likely be the first major record-breaking heat event of the summer, though the state experienced a significant hot spell in the early spring. The relatively mild summer weather has kept vegetation from reaching critical dryness up to this point. July heat has been more exceptional in the Rocky Mountains.
Lastly, bursts of lightning activity, particularly in Oregon, sparked dozens of blazes or more in early and mid July. California has dodged thunderstorms for the most part, aside from the Sierra Nevada where rain has accompanied lightning in many instances.
Fire season in California’s valleys and mountains typically peaks in late summer when days are hot and long, while the coast experiences its highest fire danger in fall from dry Santa Ana and Diablo winds.
Subscribe
There’s more to San Francisco with the Chronicle. Subscribe today for just 25¢.
This article originally published at California has dodged a bad wildfire season so far. That could change soon.