SANTA FE, N.M. >> Thousands of firefighters labored to slow the advance of destructive wildfires in the Southwest as residents braced for dangerously dry, warm and windy conditions in northern New Mexico and adjacent areas that have made the blazes hard to contain.

At least 166 homes have been destroyed in one rural county in northeast New Mexico since the biggest fire burning in the U.S. started racing through small towns east and northeast of Santa Fe on April 22, the sheriff of San Miguel County said.

Authorities on Friday morning urged people to immediately leave a string of sparsely populated canyons and forests on the fringes of the Santa Fe National Forest northwest of Las Vegas, New Mexico, where nearly 1,000 firefighters and emergency personnel were deployed.

Flames were driven forward by steady winds that were expected to persist until Friday evening. A weather update from the U.S. Forest Service described gusts as high as 66 mph (106 kph).

In a Friday afternoon briefing for the Santa Fe National Forest, operations Chief Jayson Coil said that intelligence gathered from a plane, before winds picked up, reinforced their concerns.

“The fire is moving faster than we originally had anticipated under these conditions and we still have not reached the peak of the wind,” Coil said.

One expert warned that the conditions across the drought-stricken region were a recipe for disaster on the wildlands where some timber is drier than kiln-dried wood.

“It’s a very, very dangerous fire day,” fire behavior specialist Stewart Turner said at a briefing on the edge of the Santa Fe National Forest in Las Vegas. “It’s a day that as a firefighter, we’ll write about, we’ll read studies about.”

Matthew Probst, Las Vegas-based medical director for the health clinic network El Centro Family Health, said the nearby fire has swept through impoverished communities already frayed by the coronavirus pandemic.

“Here, you’re losing meager homes, but it’s everything. It’s all they had,” said Probst, a coordinator of county health services for wildfire evacuees.

Rural families in the area were caught off guard after heading home from an early evacuation — only to be ambushed by a fast-moving fire last week.

A 79-year-old widow from the tiny community of Sapello left her house and a blue heeler cattle dog for a doctor’s appointment, with boxes packed for possible evacuation with jewelry and her 1964 wedding photos. Winds kicked up, and police said it was too late to go back for anything.

“They said, ‘No ma’am, it’s far too dangerous,’” said Sonya Berg in a phone interview Friday from an emergency shelter at a nearby middle school.

A close friend says the house burned, but Berg doesn’t want to believe it. A neighbor rescued the dog.

“I’m in denial until I go and see it,” said Berg, whose husband passed away in 2019 and was buried outside the home. “He’s up there, he’s been through the whole thing. I’m hoping the gravestone we put up is still there.”

In the Jemez Mountains east of Los Alamos, another wildfire spanning 12 square miles (30 square kilometers) crept in the direction of Bandelier National Monument, which closed its backcountry hiking trails as a precaution while central visiting areas remained open.

A swath of the country stretching from New Mexico and Colorado to Kansas and the Texas panhandle is expected to be hit the hardest by the return of weather that has generated unusually hot and fast-moving fires for this time of year, forecasters warned.

Red flag warnings for extreme fire danger were in place Friday for nearly all of New Mexico and parts of Colorado, Texas, Oklahoma and Kansas.

High winds were likely to ground firefighting aircraft in some areas, officials said.

More than 2,000 firefighters were battling fires in Arizona and New Mexico on Friday — about half of those in northeast New Mexico, where more than 187 square miles (484 square kilometers) of mostly timber and brush have been charred.

Fire lines were bolstered outside the rural New Mexico community of Ledoux in efforts to save structures.

Sheriff Chris Lopez, of New Mexico’s Miguel County, announced the fire there has destroyed at least 166 homes, 108 outbuildings and three commercial buildings. He joined authorities in neighboring Mora County in pleading with residents to pay close attention Friday to sudden changes in closures and evacuation orders.

“Falling trees, possibly falling power lines, that’s the kind of winds we’re looking at,” Lopez said.

In northern Arizona, authorities are nearing full containment of a 30 square-mile (77 square-kilometer) blaze that destroyed at least 30 homes near Flagstaff and forced hundreds to evacuate. A top-level national management team turned it back over to the local forest Friday.

“It’s pretty stable for the most part,” said Coconino National Forest spokeswoman Randi Shaffer. “We’re not seeing any forecasted crazy weather patterns. We have fire crews monitoring, all of our suppression efforts have been holding.”

Some residents near another fire 10 miles (16 kilometers) south of Prescott haven’t been allowed back home. Firefighters have about one-third of the 14 square-mile (37-square-kilometer) fire’s perimeter contained. Lighter winds were expected into the weekend, but low humidity will be a concern, fire officials said.

Elsewhere, one national wildfire management incident team continued to oversee a large prairie fire in Nebraska, where more than 200 firefighters were battling a blaze that has been burning since last week.

About 68 square miles (176 square kilometers) of mostly grasses and farmland have been blackened near Nebraska’s state line with Kansas. Several homes were destroyed and at least one person was killed. That fire was 97% contained Friday.