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Coastal fire a harsh reminder that fire season is longer, more intense

As a mid-spring brush fire ate 20 homes in Laguna Niguel this week, part of the lesson seemed clear: There’s no such thing as a traditional fire season in California anymore.

In a world changed by global warming, fires can pop up any time, even in months once considered wet enough to be fire safe. The sad images of homes engulfed by what soon was christened the Coastal fire seemed to be the exclamation point.

But what if that’s only half the story? What if the new reality is more subtle, and possibly more dangerous?

These days, more fires do indeed pop up during months – late winter and early spring – that a generation ago were usually fire-free. And those months now are followed by an amplified version of what used to be peak fire season, mid-summer through fall, with region-altering mega-fires becoming essentially routine.

Fires happen earlier. They’re bigger. And they’re happening in places where fire once didn’t pose a routine threat.

Experts who fight and study fires say that’s the real lesson of the Coastal fire, and it’s just part of a broad shift in fire risk that’s taken root in Southern California since the start of this century.

On the ground

One element of the new normal can be seen, and felt, at your feet.

“Sad to say, we’re getting kind of used to this,” said Brian Fennessy, chief of the Orange County Fire Authority, to start a Wednesday, May 11 news conference at a Laguna Niguel park about a half-mile from the neighborhood ravaged by the Coastal fire.

Fennessy was talking about the new frequency of fires in non-traditional fire months. He referenced the Emerald fire, a 150-acre brush fire north of Laguna Beach that took place in February, as another example of a blaze that happened in what once was the opposite of fire season.

What was unusual about the Coastal fire, he said, was the severity of the conditions on the ground.

When crews arrived in Laguna Niguel, they encountered routine winds and slightly cooler-than-average temperatures – and land conditions that defied the calendar. Mid-May vegetation looked like, and burned like, mid-August vegetation. And those hyper-arid conditions helped the fire move at a sprint, turning a relatively small event (200 acres) into the most damaging neighborhood conflagration to hit the county in five years, with 20 houses destroyed and 11 others damaged.

“What we saw today is not something we’re used to seeing at this time of year,” Fennessy said.

Fire-wise, the no-longer-unusual is happening in Southern California and beyond.

On May 1 there were 11 major fires burning and uncontained in Arizona, Colorado, Florida and New Mexico, according to the monthly report from the National Interagency Fire Center. That’s a full three months before traditional fire season used to kick in and it’s believed to be a record number of fires so early in the year.

The federal report said 1.1 million acres had burned in the western U.S. so far this year, a figure that is some 70% higher than what has been “average” over the past decade. The previous decade, it should be noted, was the most fire-prone in national history.

The report also noted that recent weather patterns (little but not zero rainfall; temperatures within 5 degrees of normal) have created springtime fire conditions in Southern California that, a generation ago, would have seemed appropriate in mid-July.

“The drought continues to worsen across the area, with extreme drought in the San Joaquin Valley expanding into the Sierra and the interior portions of the central coast. Otherwise, severe drought continues across most of the area, except for moderate drought south of Los Angeles County from the mountains westward.”

But the agency, like many other weather and fire trackers, now assesses fire risk in context with the recent past, when fire seasons have been transformed by climate change. That’s why, after taking into account factors as diverse as ocean surface temperature off the coast of Alaska (cooler than normal) to marine layer on the Southern California coast (thinner than normal) to the persistent drought (way, way drier than normal), the agency concluded that Southern California’s fire risk, for the next few months at least, might not be as bad as in the very recent past:

“Near to below normal large fire activity is expected from May through August due to well below normal fine fuel loading.”

Bigger, earlier, more

A year ago, researchers at UC Irvine issued a report on Southern California wildfire trends that concluded what any non-scientist, long-time resident already knew – there have been a lot more wildfires in the region during this century.

But the report, from UCI’s Department of Civil & Environmental Engineering, wasn’t anecdotal. It was based on data from thousands of California fires over the previous 100 years. Researchers looked at fire events in two distinct camps, those that happened from 1920 through 1999 and those that happened from 2000 through 2020.

The data was clear: Fires are steadily becoming more frequent and more destructive.

“Each new year of the 21st century has been a record-breaker in terms of wildfire damage in California,” said report co-author Tirtha Banerjee, a professor of civil & environmental engineering at UCI.

The report also looked at some details. Researchers noted that while big fires (500 acres or more) are less frequent, they generate the most death and destruction – accounting for about 20% of all events and 97% of the acres burned.

“When fires get large, their deadliness increases,” Banerjee said.

What’s more, this century also has seen the emergence of two seemingly disparate trends, the rise of so-called “extreme” fires – 10,000 acres or more – and the number of small, human-caused fires in remote locations.

And as the fire season has extended, and fire risks have grown, the areas touched by fires have expanded.

From 1920 to 1999, the one part of Southern California that was rated by fire officials to experience “very high wildfire density” was Los Angeles County. But in this century, the areas taking on that official label have expanded throughout the region to include Ventura County and portions of Riverside, San Diego and San Bernardino counties, according to the UCI report.

This century also has seen the emergence of the coast as a fire zone. Though big fires hit the Malibu Canyon area, and other coastal spots, last century, such events typically were rare. In the 2000s, the UCI report found, virtually every coastal county in California has seen higher risk, with the bulk of coastal fires happening between Monterrey and San Luis Obispo counties.

The UCI report also backed up the idea that the fire season is what the Coastal fire suggests it is – year-round and more intense.

Without looking at any report, and relying on what he’d seen his crews handle in recent years, Orange County Fire Authority Chief Fennessy stood near the burned homes of Laguna Niguel and said:

“Unfortunately, this is what we’re going to be experiencing over the next several months and the next several years.”


Source: Orange County Register

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