Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ US https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ California forest fire generates its own lightning as it more than doubles in size

California forest fire generates its own lightning as it more than doubles in size

Plum of smoke and fire rise over Frenchman Lake as the sugar fire, part of the Beckwourth Complex Fire, burns in the Plumas National Forest, California, Thursday, July 8, 2021. (AP Photo / Noah Berger)

Smoke and fire are rising over Frenchman Lake as the sugar fire, part of the Beckwourth Complex Fire, burns in the Plumas National Forest on Thursday. (Noah Berger / Associated Press)

A forest fire in northern California more than doubled in size from Friday to Saturday, sending a massive cloud of smoke and ash that, combined with the dry heat, generated its own lightning and created dangerous weather conditions for firefighters, authorities said.

The sugar fire, which ignited on July 2, had spread to 54,421

acres and was 8% contained as of Saturday morning. The fire, now the state’s largest of the season so far, was one of two triggered by lightning in the Plumas National Forest, which together has been called the Beckwourth Complex Fire. The second, the Dotta Fire, started on June 30 and was 670 acres and 80% contained in early Saturday.

Burned by a heat wave in the middle of the week that exacerbated already hot, dry conditions, the sugar fire made a big run on Friday and triggered new evacuations to parts of Plumas and Lassen counties as well as part of Washoe County, Nev. Washo County evacuations were lifted Saturday, but residents were advised to pay attention. About 2,800 people remained under evacuation orders or warnings, officials said.

Firefighters relied on another day of extreme conditions in the midst of even warmer temperatures.

“As long as it’s so hot and we have these low humidities, it’s a little hard to tell when and where to catch this,” said Lisa Cox, information officer for Beckwourth Complex Fire.

Firefighters watched group fires and long-range spotting as flames tore through timber stands, she said.

“It increases the rate of fire spread because the fire actually moves between the treetops,” she said. “Basically, it just runs across the trees until it runs out of trees.”

Such intensity combined with hot, dry, unstable conditions could generate a thunderstorm cloud, as the fire did Friday afternoon when the incident meteorologist observed cloud to cloud lightning, Cox said.

So-called pyrocumulonimbus clouds can again cause the fire to spread even faster – in addition to lightning, they can create erratic, glowing winds.

“Yesterday, our operations staff reported that they spotted about a mile in front of their heads,” Cox said.

Pyrocumulonimbus clouds – as well as pyrocumulus clouds that are similar but do not produce thunderstorms, tend to rise in the afternoon when it is warmest and can pose an additional danger when they fall when things cool down.

“Later in the afternoon, the cloud collapses and creates a haze of heavy smoke, embers, stuff like that, and it can actually create additional fire behavior,” Cox said, noting that the crash could hurl sparks miles in front of the main fire. . At the same time, smoke also reduces visibility by turning off firefighting aircraft, she said.

The extreme fire behavior has made it dangerous for hand crews to fight the fire directly.

“It’s too dangerous, at least during the day,” Cox said. “At night, they can try to get around fires that are formed. It just really depends. “Crews have prioritized which spot fires to attack by performing infrared mapping and then looking at where communities are at risk,” she said.

Crews performed more direct firefighting – digging a line around the fire with tools and manually – on the southern flank, she said.

“But it’s definitely more dangerous with a tactic right now, just because of how this brand is behaving,” she said. “So we also have many indirect firefighting efforts. This includes the construction of bulldozer lines around affected communities. ”

Crews carried out strategic firings from the bulldozer lines overnight in an attempt to control how fire enters the area, she said. They also constructed indirect dozer lines along the northeast flank of the fire closer to the Nevada border to try to protect homes in the Constantia Road area, she said.

Firefighters were dispatched in front of the fire to mirror several emergency areas where they could put out the fire, she said.

About 1,256 employees fought the fire, including a robust air strike, Cox said. Still hardness in this year’s fire season – California has already seen more than twice as many acres burned compared to the same time last year – was a strain on resources.

“Fire incidents from across the state are competing for resources, and it’s just hard to get all the qualified people for each incident to be fully staffed,” she said. “And that includes both our overall management of the fire and crews on the ground.”

Dangerous conditions were expected to persist over the weekend, with the National Weather Service issuing an excessive heat warning that was in effect though Monday.

Temperatures in the lower valleys near the fire were expected to reach anywhere from 100 to 106 degrees, said Dawn Johnson, a meteorologist at the National Weather Service in Reno.

It was the result of a large high-pressure area centered over California, Nevada and Arizona that produced an effect similar to the heat dome over the Pacific Northwest, which generated record temperatures last month, Johnson said.

“You just get this feedback where it gets hot for several days,” she said.

Meanwhile, afternoon humidity has been between 8% and 12%, creeping up to just 25% to 30% overnight, while overnight temperatures have been warmer than normal, both hampering firefighting efforts, Johnson said.

In fact, the air is so dry that some of the water and retardant lost by planes on the sugar fire has evaporated before hitting the ground, Cox said.

The fire was 70% contained on 490 acres on Tuesday four days after it started. By Wednesday morning, it had grown nearly fivefold to 2,365 acres, and the enclosure dropped to 28%.

Officials attributed the increase in fire activity to the heat, which began to intensify midweek, further baking drought-stressed vegetation and promoting the development of the giant smoke fume that helped the fire grow even more.

“It’s the temperatures that are constantly drying out these fuels and the low humidity,” Cox said. “It’s a cumulative synergistic effect.”

Winds are also being adapted to the topography of the gorge to further drive fire growth, she said.

There was nothing about whether the fire had destroyed structures. Injury assessment teams were okay but had not yet been able to conduct a review, Cox said.

The fire threatened high-voltage power lines, large fiber-optic lines and two Union Pacific railroads, she said.

A railroad line or subdivision was closed after flames damaged a bridge, Union Pacific spokeswoman Kristen South wrote in an email. Union Pacific water trucks remained in the area of ​​spray structures Saturday, she wrote.

The fire was less than two miles from US 395 as of Saturday morning. Firefighters tried to keep it west of the highway but said it could spot it. Still, Cox said the terrain in this area is flatter and the fuels lighter, so firefighters were sure they would be able to get the upper hand there.

Authorities remained concerned about extreme fire behavior, including long-range spotting, which could cause more fires to take hold, Cox said. Because of the unpredictability, they urged the public to monitor alarms issued by local law enforcement agencies and be ready to evacuate.

“If people want to help firefighters out,” Cox said, “that’s the best way they can help firefighters.”

This story originally appeared in the Los Angeles Times.

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