Just as the western United States is bracing for another season of monster wildfires, El Niño has kicked into gear and added its weird weather to the mix.
For some parts of North America El Niño could be a blessing – suppressing hurricanes in the North Atlantic or bringing rain to parched California. But for other parts it could set up more megafires, say wildfire experts.
A lot depends on how this fledgling El Niño grows in coming weeks and months.
World's Oldest Fire Has Been Burning for 5,500 Years
El Niño is a worldwide climate event linked to a pool of warm water forming in the eastern equatorial Pacific Ocean. That pool has formed and been very gradually getting warmer and has been warming and adding moisture to the air there – a key step for El Niño to make changes in atmospheric circulation.
"Some of the models have it developing into a strong El Niño event," said Mike Halpert, Deputy Director of NOAA's Climate Prediction Center. "That's the one that folks in California are hoping for."
The last really potent El Niño was in 1997-1998. That event was too strong, however, causing more than a half billion dollars in flood damages to the state. For that reason a moderately strong El Niño would probably be preferable, but even that could have major effects on where wildfires are likely to burn this year.
A moderate to strong El Niño could, for instance, cool and moisten the Southwest, moving the greatest megafire threat up into parts of Washington, Oregon and northern California, explained wildfire expert Wally Covington of Northern Arizona University in Flagstaff, Ariz.
"The Southwest is looking pretty good," said Covington. If the trend continues, it will enable wildland firefighters to move their forces north, closer to where the greatest danger lies, he said.
Intense Wildfire Season Expected in West
Some wildfires in the Southwest might even be allowed to burn in order to lessen the fire fuel on the land and help prevent more dangerous fires during dry years.
On the other hand, the El Niño/wildfire connection is not so clear for California's chaparral country, Covington explained. Unlike forests, the shrubby chaparral of California's coastal hills and mountains grows quite fast and is extremely flammable, so it can burn more often and under a wider range of conditions.
A big concern, says Covington, is what happens after fires start. In many places parts of the West higher temperatures and decades of fire suppression have led to forests that are severely overgrown and ready to burn explosively.
"Another thing that's driving megafires is the severe drought coinciding with [high winds]," Covington said. Those winds – which are part of a larger shift in global climate – serve as billows to fires, growing them hotter and far larger than ever before.
"Around the year 2000 we started to see large areas of landscape chock full of fuel and droughts, punctuated by high wind events," said Covington. "The result was stunning fires."
In the 1970s a three- or four thousand-acre fire was considered a very large fire, he said. Now megafires exceed 100,000 acres. "Now we'd welcome a three or four thousand acre fire."
Whether or not El Niño exacerbates or quells this year's megafires remains to be seen. Right now the warm waters off South America continue to tease climate forecasters and not everyone is ready to place bets.
"The signals are much weaker in the summer," said Halpert. Often El Niños don't really hit their stride until the fall, he added. "We're right on the dividing line between weak-to-moderate effect. So it would probably not be good to bet the house on it. Over the next few months we expect the ocean to warm further."
In terms of wildfires, however, the current effects is enough to bank on.
"We're pretty confident that this moderate-to-weak El Niño will be in place," said Covington.