MILWAUKEE (REUTERS) - Fierce wind gusts and brutally bone-dry conditions are expected on Thursday (June 14) across a five-state region where firefighters are wrangling several unrelenting wildfires that have forced thousands of residents to flee their homes.

Red flag warnings have been issued for parts of Nevada, Arizona, Utah, Colorado and Wyoming, where winds gusts could reach 65kmh and humidity drop to 5 per cent throughout the day, the National Weather Service said.

Weather conditions along with possible dry lightning from thunderstorms could contribute to "extreme fire behaviour" on Thursday in the south-west United States, where more than two dozen wildfires are currently burning, the service warned.

The largest and most threatening blaze, the 416 Fire, has scorched 11,088ha of drought-parched grass, brush and timber at the edge of the San Juan National Forest near the south-western Colorado town of Durango.

Crews had contained 15 per cent of the blaze, fire officials said.

Thursday's weather outlook has prompted fire officials to issue pre-evacuation orders for 163 residences and two businesses, while some 1,400 homes remain under evacuation orders, La Plata County officials said.

The City of Durango closed all open spaces and trails and prohibited smoking on public property and fire-setting anywhere in the city.

The 416 Fire and a separate blaze burning nearby, the Burro Fire, also prompted state parks officials to close several wildlife areas to the public.

The US Forest Service has closed all 728,434ha of the San Juan National Forest to visitors.

About 96km west of Denver, a blaze called the Buffalo Fire prompted the evacuation of nearly 1,400 homes after blackening 36.8ha, officials in Summit County said.

Its containment was listed at 20 per cent by fire officials.

No people have been injured or structures lost in the Colorado fires, while nine homes were destroyed in a small wildfire in Utah.

Firefighters were hoping for some relief from a promising shift in weather patterns forecast for Friday, some of it associated with Hurricane Bud, which on Wednesday was off the Pacific coast of Mexico.

In southern Wyoming near the Colorado border, the Badger Creek Fire in Medicine Bow National Forest has grown to more than 2,832 acres, as evacuation orders were expanded to nearly 400 homes in Albany County, according to the Inciweb online US fire information service.

The Wyoming fire containment was listed as zero per cent by fire officials.