By Livia Albeck-Ripka
NYTimes News Service
When rain pummeled California in October, many breathed a sigh of relief: At least in some parts of the state, the worst of the fire season, experts said, was most likely over.
The following month, however, precipitation was scarce. In December, it rained again, smashing records. Now, some parts of the state have barely seen another drop of water since early January.
“It has been both an unusually dry and an unusually wet winter,” said Daniel Swain, a climate scientist at the University of California, Los Angeles, and the Nature Conservancy.
But what do these ups and downs mean for California’s next fire season? The answer is complicated.
Before October, a vast majority of California was considered to be in “exceptional” or “extreme” drought (the highest rankings, according to the U.S. Drought Monitor). So when meteorological conditions known as “atmospheric rivers” drenched parts of the state in October and December, much of that water was sucked up by the parched landscape.
The hot and windy conditions that followed also led the rain to evaporate quickly, drying out the vegetation that fuels fires. California’s rising snowpack, which provides moisture to the ecosystem as it melts in the spring, has since plummeted.
Historically, California’s fire season lasted a few months during the hottest part of the year. But recently it has become more year-round.
In January, typically one of California’s wettest months, a wildfire swept through Big Sur, a mountainous coastal region south of San Francisco, forcing hundreds of residents to evacuate. The scene was “pretty surreal” given California’s wet October and December, the National Weather Service said on Twitter at the time.
Although the extreme rainfall and dryness might average out to near-normal levels of precipitation, that is no insurance policy against fire, scientists say. As global temperatures warm, even in wet years, hot weather can ultimately dry out vegetation to produce droughtlike conditions.
“We still get dry years and wet years but we don’t really get cold years anymore,” Swain said. He added, “No matter what, everything still dries out.”
For now, the dry spell has a small silver lining.
The lack of rain gives fire authorities more opportunity to conduct prescribed burns that help to reduce the worst impacts of fires during the summer. And fires that ignite spontaneously during these colder months are also likely to be less intense and can help to avert worse fires in hot, dry conditions.
But without rain in the coming days or weeks, the state could begin relapsing further into drought. Last year, historically low rainfall and ongoing drought helped cause a brutal fire season that lasted several months and burned 2.6 million acres.
“I don’t think March is going to somehow bail us out,” Swain said of the likelihood that generous rain in the coming weeks would help stave off intense fires this year. “We’re seeing bad fire years almost every year.”
This article originally appeared in The New York Times.