Oregon State Forestry crews late Monday were swarming a 100-acre fire that erupted in the Illinois Valley, the latest in a series of fires that ignited over the weekend.

Monday evening's roughest fire of concern was off Reeves Creek Road where it intersects with Highway 199, according to state forestry officials.

The smoke from this fire cloaked the Rogue Valley sunset easily visible in Medford.

Fire agencies from Jackson and Josephine counties were quickly mobilized in the attack.

While Reeves Creek Road from Highway 199 to South Shore Drive was closed Monday evening, no evacuation order was issued Monday evening, according to the Josephine County Sheriff's Department.

However, local residents who need extra time to pack or get animals to safe places were urged to start planning for an evacuation.

The cause of the fire was not immediately known.

Less than a week after an energetic lightning storm kick-started 37 wildfires across Jackson and Josephine counties, another smaller fire reared its head earlier Monday.

That fire was reported in the Kane Creek area south of Gold Hill Monday, growing to about 2 acres in size before crews stopped it from spreading further.

"We fully expected these things to pop up," ODF spokesman Brian Ballou said.

It was called in at about 6 a.m., burning in a heavily wooded area six miles south of Gold Hill. The flames put off a sizeable amount of smoke, visible from Medford. Crews responded with three engines and a helicopter, and were eventually joined by a water tender and two 10-person hand crews who dug fire lines for full containment. The fire did not threaten any structures, and no one was injured.

A 20-person crew from Jackson County Community Justice remained on scene through the day to mop up the fire. Department officials said the morning's cool temperatures and lack of significant wind helped significantly in getting the flames under control.

"It's a good time of day to have one of these things pop up," Ballou said.

Fire officials say last week's lightning storm was a likely source for the blaze. The storm drifted into the area Tuesday, bringing abundant rain and lightning. Clouds shot out more than 1,200 air-to-ground strikes around Jackson County, with dozens more reported in nearby Josephine County.

The rain and hail that came with the clouds was to firefighters' advantage, however. That and lingering cloud cover made extinguishing the numerous small lightning starts manageable. That was different from July 2013's moisture-free storm that set off three major regional fire complexes across Southern Oregon that crews spent weeks putting out.

"Part of this is just due to the nature of the thunderstorms that we've had," Ballou said.

But the recent favorable fire-fighting conditions are expected to change this week. The moisture that came with last week's storms is expected to have less of a presence this time around.

A 10 to 20 percent chance for additional isolated thunderstorms is expected through Friday, which could trigger fires along the Cascade range. That's on top of a slew of high temperatures that aren't expected to drop below the high 90s and could get into the 100s, according to Weather Service.

"There's absolutely no real relief in sight with the extended fire season going into the fall," Ballou said.

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