Dry conditions and the threat of thunderstorms have fire crews on the lookout for new lightning-sparked fires today.

Dry conditions and the threat of thunderstorms have fire crews on the lookout for new lightning-sparked fires today.

The National Weather Service issued a red-flag warning for 2 to 11 p.m. today, alerting residents to extreme fire danger because of the conditions.

Weather officials predict scattered thunderstorms over the eastern Rogue Valley, Umpqua National Forest, Siskiyou Mountains, southern Cascades and Klamath Basin. These thunderstorms, combined with potential triple-digit temperatures and parched terrain, mean the chance for multiple fires to start is high, officials said.

"Significant rainfall is expected with some of the thunderstorms, but fire spread is likely in areas that do not receive wetting rain," a message from the National Weather Service reads.

The mercury has eclipsed 100 degrees since Monday, when it reached 106. Tuesday's high was 103, the 11th day of triple-digit heat this month. It's supposed to stay near 100 or hotter through Saturday, forecasters predict.

Wildfires reared up across the region Tuesday, some the result of storms last week.

The Illinois Valley's Reeves Creek fire, through forestlands near Lake Selmac 25 miles southwest of Grants Pass, remains the largest. By Tuesday afternoon, crews had called for a Level 1 evacuation of residents on nearby WildPark Lane off Highway 199. Level 1 means residents should be at the ready to evacuate because of concerning fire behavior.

After a full day of helicopters dropping thousands of gallons of water on the fire, retardant drops from tanker planes and about 150 firefighters working on the ground with engines and bulldozers the fire was 90 percent contained at 232 acres, said Oregon Department of Forestry spokesman Brian Ballou.

The fire was first reported at 6:38 p.m. Monday. Its cause remains under investigation.

Firefighter worked through the night to fully contain the fire, Ballou said.

Two smaller fires continued to burn steadily through the day in Klamath County.

The Launch fire, burning at Fourmile Lake, had grown to 100 acres Tuesday. Eight engines, two helicopters, an air tanker and a hand crew were fighting the flames. Containment numbers were not available, and the cause was under investigation.

The 25-acre Pumice Flat fire, burning in mixed conifer forestland, which includes hemlock, fir and pine trees, was first reported Monday morning and is believed to have started with a lightning storm July 22. More than 50 firefighters fought the flames Tuesday.

The park is not closed, though hikers on the Pacific Crest Trail could be impacted in the coming weeks depending on how containment efforts fair.

"It's pretty accessible," said public information officer Jan Lemons. "It's about two miles in from the south entrance road."

Ballou said additional crews were called in to help on the Reeves Creek fire so others can be ready in case new flare-ups break out.

"Everybody's aware of the urgency to get this one knocked out," he said. "We just have to wait and see what occurs.

"It's a process of fighting fire aggressively, but as smart as we can. Unfortunately, the clock is ticking."

Reach reporter Ryan Pfeil at 541-776-4468 or rpfeil@mailtribune.com. Follow him at www.twitter.com/ryanpfeil.