(CNN) -- Wildfires continued to scorch large swaths of the western United States on Sunday, with firefighters doing their best to corral a host of blazes despite high temperatures, low humidity and possible lightning in many locales.
Two of the biggest, still raging conflagrations are in Idaho's expansive Salmon-Challis National Forest, one of several places -- along with most of the rest of the Gem State as well as parts of Oregon, Utah and Montana -- where the National Weather Service issued red flag warnings through at least Sunday night.
The largest is the Halstead Fire, centered about 18 miles northwest of Stanley, according to InciWeb, a U.S. government-operated multiagency fire response website. Sparked by lightning on July 27, this blaze that's charred around 92,000 acres was still only 3% contained by midday Sunday.
The fire has prompted a number of evacuations, including that of the entire small town of Featherville on Saturday night.
Elsewhere in the same national forest, five fires have burned together to form what is known as the Mustang Complex. Weather was a challenge Sunday with temperatures soaring to the high 90s, winds blowing about 10 mph and lightning threatening to cause even more fires on top of the 85,000 acres that have already burned, InciWeb reported.
Another hotbed of activity, and headaches, this weekend was in northern California.
InciWeb described the "growth potential" of the week-old Rush Fire in the northeastern part of California near Nevada as "extreme" and the difficulty of the terrain for firefighters as "high."
While the fire was 45% contained on Sunday morning, it has scorched about 250,000 acres and could cause even more problems as it smolders near a major natural gas line and power transmission lines that run down into Reno, Nevada, according to InciWeb.
About 300 miles to the southwest, over 1,000 personnel were trying to check the Chips Fire in Plumas National Forest. The weather wasn't helping in corralling a blaze that has consumed about 45,000 acres to date since starting July 29, with temperatures near 100 degrees Fahrenheit and 21 mph winds.
Meanwhile, brand new problems were emerging like the fast-moving Ponderosa Fire, which is set in a wooded area in Tehama and Shasta counties about 35 miles outside Redding.
People living in about 2,000 residences across five or six small rural communities have been ordered to leave as a result of a fire that was first reported around midday Saturday, California Department of Forestry and Fire Protection spokeswoman Mary Ann Aldrich said Sunday.
Seven structures have been destroyed and hundreds of acres have been destroyed due to the blaze, which was 0% contained around 1 p.m. PT (4 p.m. ET) Sunday, according to Aldrich's agency.
CNN's Deanna Proeller contributed to this report.