The blaze has scorched more than 121,000 acres, or more than half the area of New York City, tearing through centuries-old settlements and vacation homes in forested mountains 48km northeast of Santa Fe.

The fire is the most destructive of a dozen blazes in the southwest that scientists say are more widespread and arriving earlier this year due to climate change.

In northwest Las Vegas, families packed trucks with boxes of photos and heirlooms and loaded livestock onto trailers, heeding police warnings for residents to get out of the area.

David Lopez, 31, chose to stay and defend his family’s two trailer homes, wetting down the earth with a hose and raking away dead grass to create a fire break.

“This is all I have – I worked really hard for it,” said the 31-year-old mechanic, who said he planned to flee once flames got within a quarter of a mile of him.

High temperatures and erratic winds kept the fire spreading at “dangerous speeds and in different directions”, the Santa Fe National Forest, administered by the US ForestService, said in an alert.

“This is a long-term event and we don’t anticipate having ‘control’ of this fire any time soon,” it said, adding that strong winds were expected most days for the next two weeks.

As fire approached from the north and west, the university town of 14,000 staggered evacuations, with another 4,000 to 5,000 people on standby to go, said San Miguel deputy county manager Jesus Romero.

The state psychiatric hospital in Las Vegas evacuated 197 patients to other facilities, the New Mexico health department tweeted.

Burning since April 6, the fire has destroyed hundreds of properties and forced the evacuation of dozens of settlements in the Sangre de Cristo Mountains, but there have been no reports of fatalities.