A fast-moving wildfire destroying homes in northwest Reno, Nevada, was human-caused and remained uncontained on Sunday, authorities said, as officials urged roughly 90,000 people to evacuate. At least six people were injured.

The Hawk Fire ignited Saturday and rapidly expanded to 20 square miles (53 square kilometers) as it swept across the Peavine Peak area of the Humboldt–Toiyabe National Forest, where rugged foothills packed with homes and businesses sit near the California state line. Humboldt–Toiyabe is the largest U.S. national forest outside Alaska, covering more than 6 million acres across Nevada and parts of eastern California.

Terrain like the Peavine foothills, where neighborhoods press against fire-prone open land, is known as the wildland-urban interface — a land-use pattern that federal researchers say has expanded rapidly across the United States and is where most wildfire structure losses occur.

The blaze moved exceptionally fast Saturday night, leaping over fire trucks and preventing responders from reaching hotspots while residents were still trying to flee, Washoe County Sheriff Darin Balaam said.

“It was extremely confusing,” the sheriff said, describing how shifting winds drove the flames in different directions.

Several structures were destroyed. The injured included three civilians and three first responders, officials said. They declined to provide additional details on how the fire was started, saying the cause remains under investigation.

The human-caused designation means the blaze was sparked by people rather than natural ignition sources, which are overwhelmingly lightning. Federal wildfire data shows human activity starts roughly 85% of wildfires in the United States by count, though lightning-sparked blazes account for a larger share of the total acreage burned.

Unpredictable fire expands the danger zone

About 42,000 residents were under mandatory evacuation orders as the “GO NOW” zone expanded to the edge of the University of Nevada. Another 45,000 people were in the adjacent evacuation warning zone. The warning-then-order sequence mirrors the “Ready, Set, Go!” escalation model used by fire agencies across the West, in which residents are urged first to prepare, then to be ready to leave at a moment’s notice, and finally to evacuate immediately. Authorities implored everyone in both zones to leave and be prepared to stay away for several days, warning that shifting and strengthening winds were expected to make the fire even more unpredictable.

“Please get out if you can right now,” the sheriff said.

Nevada Gov. Joe Lombardo declared a state of emergency in Washoe County and mobilized the Nevada National Guard, deploying two helicopter crews to support aerial firefighting and 60 troops to help police safeguard evacuated neighborhoods. A total of 800 fire personnel were also responding.

Nearly 10,000 NV Energy customers in Washoe County remained without power Sunday, down from 60,000 on Saturday. Portions of U.S. Route 395, a major north-south highway, were closed because of the fire. Reno, home to more than 280,000 residents, is the largest city in Nevada outside the Las Vegas metropolitan area.

Washoe County emergency officials opened the Reno-Sparks Convention Center to evacuees but said they could not bring pets — small and large animals were to be taken to two other locations. Reno casinos offered discounts on hotel rooms to evacuees.

A family races to grab possessions, loses its home

Cari Kieffer said a video posted on social media showed her house entirely burned down, with only a scorched basketball hoop still standing.

“I woke up this morning and just started crying — all my kids, they lost everything,” Kieffer said Sunday. “We lost all our stuff. Everything we own is gone.”

Kieffer had been watching her son’s football game Saturday when she learned that their home on the outskirts of Reno lay inside the evacuation zone. A fire-tracking application the family used had been lagging significantly behind the blaze’s actual location, she said, leading them to believe firefighters had kept the flames from their neighborhood.

Instead, Kieffer, her husband and their four children, ages 3 to 16, raced to save their dogs and whatever possessions they could retrieve. Ash rained down, and the wind blew like an oven blast from a wall of flames advancing down the hillside toward their neighborhood, she said.

“I kept looking outside and the flames just kept getting closer and closer every time I looked,” Kieffer said. “I was like, we gotta go like now.”

With her eyes watering and throat burning, Kieffer grabbed a handful of clothes, a Bible, her wedding photos and her mother’s ashes. In the frenzy, as firefighters yelled at her family to leave immediately, she said she forgot the family’s birth certificates and was unable to salvage her childhood photos.

The family drove to a friend’s home but had to evacuate again. Later Saturday evening, they learned their own home was gone.

A mountaintop home goes up in flames

Jaida Hargrove’s grandfather, Rick Arrate, lived alone on Peavine Mountain, which overlooks Reno and Sparks. Firefighters used a bulldozer, cut down trees and applied fire retardant in an attempt to contain the flames, Hargrove said.

“They all thought it would be OK,” she said. “And then, in about 30 minutes, the winds just changed and it came way too fast.”

Arrate and the firefighters were quickly forced off the mountain. “All he was able to take with him was his two golden retrievers,” Hargrove said.

Arrate spent Saturday night with Hargrove’s parents, his next steps unknown. Separate GoFundMe crowdfunding campaigns were set up to assist Arrate and the Kieffer family.

The fire wasn’t troubling to some at first

The fire was so small Saturday morning that it wasn’t even a concern, said Tyler Duvall, who went camping over the weekend. By the next day, his house was in the evacuation zone.

“The wind really blew it up,” Duvall said.

Fifteen new fires popped up across Nevada on Saturday alone. Months of dry weather and a record lack of snow this past winter across the American West have created prime fire conditions. Earlier this month, wildfires in eastern Washington state forced the evacuation of 60,000 people in the Spokane area, while three wildfires north of Reno drove more than 13,000 residents from their homes.

A Nevada newcomer gets a rude welcome to Reno

Ted Melden, a retired police officer and firefighter, has seen his share of Mother Nature’s fury since moving to Reno with his wife earlier this month from Chapin, South Carolina. So far, he has experienced a hailstorm with flash flooding, two different power outages and, now, the second wildfire incident in the region in two weeks.

“Just another natural disaster,” Melden said.

In the two years he lived in South Carolina, Melden said Hurricane Helene knocked over trees in his yard, while a tornado did some damage in his neighborhood.

For now, Melden has not been ordered to leave his home, but he has his bags packed just in case.

“You just have to roll with the flow and be ready,” he said.

David Barb returned from a weekend hunting trip to find the fire had leveled his taxidermy shop, but his house nearby appeared to have been spared thanks to workers with a landscaping company who cut a fire break, he said. His wife was home when the fire started on the other side of the mountain and later evacuated to a friend’s house.

“I’m kind of devastated, but thank God everyone’s safe,” he said Sunday.

Places just outside the evacuation zone keep watch

The University of Nevada — formally the University of Nevada, Reno, the state’s flagship land-grant university founded in 1874 — where many of the 20,000 undergraduates moved into their housing this weekend, was just outside the evacuation zone Sunday.

Two hospitals evacuated patients, and the sheriff said his office was keeping a close watch on whether to evacuate the county jail.