A cold weather front was helping to quell wildfires across several western US states on Tuesday but authorities warned the risk of further blazes across the region remained high. US Forest Service officials said a fire in California's Inyo National Forest that has scorched more than 35,000 acres (14,164 hectares) was 80 percent contained as clouds and higher humidity levels came to the aid of fire crews.

However, forest service spokeswoman Pam Bierce said thunderstorms forecast for later this week, bringing the threat of lightning bolts igniting the tinder-dry countryside, remained a cause for concern.

"The weather is kind of a double-edged sword," Bierce told AFP. "On the one hand the milder conditions are helping firecrews, but the flipside is that the same kind of weather that started these fires is expected later this week.

"While we expect to have 100 percent containment tomorrow we remain vigilant."

Many large fires continued to rage throughout California however, with a 22,366-acre (9,050 hectare) blaze in eastern Plumas National Forest only 21 percent contained as of early Tuesday.

And in other sun-baked regions across the nation there was no let-up.

According to figures from forestry officials, a total of 67 fires were being tackled across the United States, most of them in the west.

Forty-five fires were described as active while 22 had been fully contained. In total more than 1.2 million acres (485,000 hectares) had been burnt by the separate infernos.

In Hot Springs, South Dakota, residents evacuated on Saturday after a fire that left one person dead were finally allowed to return home although the blaze remained only 40 percent contained.

Flames fanned by gusty winds were making life difficult for around 500 firefighters deployed to tackle the incident, which erupted on Saturday after lightning lashed the area.

So far the fire has destroyed around 9,900 acres (4,000 hectares) and officials warn the risk of it spreading further is high.

Officials in Boise, Idaho, meanwhile were nervously monitoring the progress of a fire that erupted in rugged, woody terrain, 45 miles south of Silver City.

The fire has already claimed 18,000 acres (7,300 hectares) and is only five percent contained.

A record dry winter and soaring temperatures across California and neighboring states have left the parched region unusually vulnerable to wildfires, officials say.

Source: Agence France-Presse