Wind-driven bushfires have destroyed hundreds of structures in northern New Mexico and forced thousands of people to flee mountain villages as blazes burn unusually early in the year in the parched US southwest.

Two fires merged northwest of Las Vegas and raced through 25 kilometres of forest driven by 120km/h winds, destroying more than 200 buildings, state authorities said.

To the northeast, a fire about 55km west of Taos doubled in size to become the largest burning in the United States, forcing the evacuation of a scout ranch and threatening several villages.

The blazes are the most severe of nearly two dozen in the US southwest and raised concerns the region was in for a brutal fire year as a decades-long drought combined with abundant dry vegetation.

“We have a longer, more dangerous and more dramatic fire season ahead of us,” New Mexico Governor Michelle Lujan Grisham told reporters, adding the state had 20 active fires following Friday’s “unprecedented” wind storm.

The Calf Canyon and Hermits Peak fires near Las Vegas combined to burn 17,100 hectares, an area larger than Florida’s Disney World.

Evacuations expanded to half a dozen more communities including the village of Mora, the governor said.

Climate change has lowered winter snowpacks and allowed larger and more extreme fires to start earlier in the year, according to scientists.

-AAP