SOUTH LAKE TAHOE, Calif. — They sent thousands of firefighters, 25 helicopters and an arsenal of more than 400 fire engines and 70 water trucks. Yet the fire still advanced.
They dropped retardant chemicals through an ash-filled sky and bulldozed trees and brush to slow the march of the flames through the steep and rugged terrain of the Sierra Nevada. Yet the fire still advanced.
Bursting across a granite ridge into the Lake Tahoe basin, the Caldor fire now threatens tens of thousands of homes and hotels that ring the lake.
On Tuesday, the smoke-choked streets of South Lake Tahoe, the most populous city on the lake, were deserted, save for police patrol cars and an occasional convoy of fire vehicles. Thousands of residents and tourists had been evacuated the day before.
The lake, renowned for its bright blue hues and the evergreen forests that surround it, was smothered in a slate of sickly orange-gray haze. On the Nevada side of the border, which has not yet been evacuated, one industry was still limping along: a trickle of gamblers sat at slot machines to the whooshing sound of large air purifiers that attempted to keep out the pungent smoke. The air quality index was nearing 500, a level considered hazardous.
Battling the Caldor fire has been humbling and harrowing for California firefighters. Experts believe the challenge is a cautionary tale for future megafires in the West and lays bare a certain futility in trying to fully control the most aggressive wildfires.
“No matter how many people you have out on these fires, it’s not a large enough work force to put the fire out,” said Malcolm North, a fire expert with the U.S. Forest Service and a professor at the University of California, Davis.
“You can save particular areas or particular homes,” Professor North said. “But the fire is pretty much going to do what it’s going to do until the weather shifts.”
On Monday, propelled by strong winds, the fire crested a granite ridge that officials had hoped would serve as a natural barrier. Embers leapfrogged past firefighting crews and descended toward the valley floor just miles from South Lake Tahoe. By early Tuesday, the fire had taken hold in the Tahoe basin. Stands of pine ignited by flying embers were fully engulfed in flames, casting a bright orange glow into the night sky.
It was only the second time, officials said, that a wildfire that began on the western slopes of the Sierra Nevada crossed into the eastern side. The first was also this summer: the Dixie fire, the second largest in California history. No deaths have been reported in either fire.
The authorities say about 27,000 firefighters were battling blazes across the country, about 15,000 of them in California. All national parks in California will be closed by Tuesday night. Hundreds of soldiers and airmen and several military aircraft have been sent by the National Guard. But the resources are no match for the ferocious blazes, which continue to outpace firefighters and explode across the state.
The blazes in Sierra forests have exposed the domino effects of climate change on firefighting challenges: Frequent heat waves and overall higher temperatures have desiccated West Coast flora, making it more vulnerable to large fires. Droughts have weakened trees, encouraging insect infestations that have contributed to the deaths of close to 150 million trees. This creates more fuel for fires.
Scientists say there is also a correlation between global warming and the increased wind conditions that have fanned fierce wildfires across the state. And they point to a need for better forest management, thinning out some of the thickest woods.
What characterizes the megafires of recent years, experts said, is their tendency to launch embers far ahead of the main fire front — sometimes by miles — and for the embers to land on parched terrain that is instantly combustible. This can rapidly expand the perimeter of the fire, which hops over one of the main containment tools: the bulldozed areas, known as fire breaks, that create a line of containment.
The Tubbs fire in October 2017 jumped over what would normally be considered a formidable fire break — a six-lane freeway — and went on to incinerate 1,200 homes in the residential community of Coffey Park.
“These spot fires are causing a lot of havoc,” said Craig Clements, a professor of meteorology and the director of the Wildfire Interdisciplinary Research Center at San Jose State University, a group that is modeling the spread of the Caldor Fire.
“There’s just fire all around,” Prof. Clements added, “and that makes it very difficult to suppress.” As a measure of how combustible the landscape has become, other scientists have calculated that embers have a 90 percent chance of becoming spot fires once they land.
The chaotic way these megafires spread was on display in the hills above South Lake Tahoe on Monday. Kyle Hukkanen was leading a crew of 12 inmate firefighters armed with axes, shovels and chain saws. They bounded down a steep hillside of granite boulders and evergreen trees until they reached a spot where wisps of smoke were rising from the ground.
They dug and sprayed the smoldering fire with water before ascending back to their idling truck. “This is not good,” Mr. Hukkanen said as gusts of wind fed the spot fire on the hillsides. The radio crackled with reports of spotting farther down the mountain toward South Lake Tahoe, and Mr. Hukkanen and his crew disappeared down a smoke-shrouded road.
Fire specialists say some firefighting tools are appropriate on a smaller scale but outmatched by the huge fires of recent years.
In the hills and gullies where the Caldor fire has burned 190,000 acres over the past two weeks, helicopters dropped large buckets of water — thousands of gallons at a time — but they hardly seemed a match.
“That’s great for protecting a neighborhood, but when you think about the size of a 750,000-acre fire, that’s nothing,” Professor North, the U.S. Forest Service expert, said of dropping water or retardant in large swaths of forest.
He and others added that the Sisyphean task of fire containment pointed to a desperate need for better mitigation.
Controlled burns that embrace Indigenous methods to use “good” fire to fight destructive megafires has become an increasingly accepted method in recent years, but experts say that the state has a lot of catching up to do.
Until then, attempts to suppress fire are inevitably required to save lives and property. In the past year, California spent more than $1 billion on emergency fire suppression efforts but slashed its prevention budget. This year’s budget includes more than $500 million for fire prevention, Gov. Gavin Newsom said in April.
Still, resources remain strained. The U.S. Forest Service has struggled to retain federal firefighters, who earn around half of their state counterparts’ pay at Cal Fire. When the Caldor Fire ballooned to 6,500 acres in mid-August, just 242 firefighters had been assigned to it. Eventually, hundreds more were redeployed from the Dixie Fire, which has so far razed more than 800,000 acres and was still less than half contained by Tuesday morning.
On the receiving end of the worsening fires are the residents who wonder where, if anywhere, will be safe from wildfire.
Among the evacuees from South Lake Tahoe on Monday were Darren Cobrae, a real estate investor, and his partner, Stephanie Cothern, who was driving the couple’s car toward the Nevada state line.
Inside were bags of clothing, two large parrots and three dogs, Banana, Freddy and Copper.
Mr. Cobrae said he moved to South Lake Tahoe from Southern California, where his home was nearly burned in a wildfire in 2007.
“I figured I would be safe in this city,” Mr. Cobrae said. “And now this,” he said, pointing to a sky thickening with smoke.