Wind-driven wildfires destroyed hundreds of structures in northern New Mexico and forced thousands to flee mountain villages as blazes burned unusually early in the year in the parched US south-west.

Two wildfires merged north-west of Las Vegas, New Mexico, and raced through 15 miles (24km) of forest driven by winds over 75mph (121km/h), destroying more than 200 buildings, state authorities said.

To the north-east, a fire about 35 miles 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 wildfires are the most severe of nearly two dozen in the US south-west and raised concerns the region was in for a brutal fire year as a decades-long drought combined with abundant dry vegetation.

By Saturday, five counties in New Mexico were under a state of emergency after the governor, Michelle Lujan Grisham, issued one for Mora county. She had declared states of emergency for Colfax, Lincoln, San Miguel and Valencia counties on Friday.

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

Winds and temperatures in New Mexico diminished on Saturday but remained strong enough to still fan fires, and dozens of evacuation orders remained in place.

Over 200 structures have burned, Lujan Grisham said, not providing specifics on locations or the numbers of homes included in that count.

She appealed to residents to refrain from using fireworks or burning trash and to evacuate when fire warnings are issued. “You need to leave. The risks are too great,” she said.

The Calf Canyon and Hermits Peak fires near Las Vegas combined to burn 42,341 acres (171 sq km), 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.

West of Taos, the Cooks Peak fire nearly doubled in size to 48,672 acres, forcing the evacuation of the Philmont Scout Ranch and threatening the village of Cimarron.

New Mexico as of Saturday had the most major wildfires burning of any state, though neighbouring Arizona also had large fires, where flames stretching 100ft (30 meters) raced through rural neighbourhoods near Flagstaff this week.

Elsewhere in the region, the fire danger in the Denver area on Friday was the highest it had been in over a decade, according to the National Weather Service, because of unseasonable temperatures in the 80s (26C-32C) combined with strong winds and very dry conditions.

Reuters and Associated Press contributed to this report