Fire season still has not hit its peak, yet the North Coast has been aflame for weeks with more than 100,000 acres scorched or still burning.

Waves of fires have torn through mostly remote and rugged terrain in wildlands such as the Mendocino National Forest and in dry grassland along Highway 101. Lake County has been nearly surrounded by fire, smoke and charred earth.

"We are having more large and damaging fires than we've had in the last couple of years," said Cal Fire Battalion Chief Ben Nicholls, who heads fire investigations for the Sonoma-Lake-Napa unit. "The fuels are ready to burn."

The only good news is that no population centers have been threatened. That, however, is not much satisfaction to folks like Duane and Dorothy Furman, who have lived on Scotts Valley Road for about 50 years and Tuesday were within about a mile of the 4,618-acre Scotts Fire on North Cow Mountain in Lake County.

They were prepared for the worst, with their most important belongings packed into a horse trailer ready to go, Dorothy Furman said.

"It's scary, you're not real sure how the fire will move," Furman said.

The next six weeks will be critical on the North Coast with the land parched from summer and autumn winds picking up, said Ryan Walbrun, a National Weather Service incident meteorologist dispatched to the Scotts Fire.

"I was just looking out the next 10 days. There is no hope of any rain. In fact, it looks warmer and drier," Walbrun said. "There's no relief in sight."

A dry inland wind from the north was forecast for later this week, what Walbrun called a "disconcerting" prediction for a region hit with an outsized number of large fires before fire season peaks in September and October.

"We will be watching," Cal Fire spokesman Daniel Berlant said. "When you start getting winds, that's when we start to see erratic fire behavior."

Cal Fire has fought 4,775 wildfires from Jan. 1 to Sept. 8 across the state, shuffling about 7,000 permanent and seasonal firefighters from fire to fire. The state fire agency has spent about $134 million of emergency funds on wildfires since July 1.

The year's number of wildfires is about 19 percent above the average for the past five years.

A dry winter left vegetation starved for moisture. Rain from several late spring storms simply "wasn't enough," Berlant said.

Fires are burning hotter and, instead of sticking to low brush as many do, are rising into the timber.

"It's indicative of the fact that the fuels are very dry," Walbrun said. "Any starts have the potential to get big in a hurry."

On July 7, a fire that began on the east side of Mendocino National Forest ripped through tens of thousands of acres in just a few days. Called the Mill Fire, it eventually spread through 30,000 acres.

Although much smaller at about 8,000 acres, the Wye Fire east of Clearlake Oaks destroyed at least one home among other structures and devoured farms and ranch land.

A lightning strike from a dry thunderstorm on Aug. 18 started the North Pass Fire, which now sprawls across nearly 42,000 acres east of Covelo.

The middle fork of the Eel River helped limit the fire's growth, which firefighters have been holding at about 97 percent containment, said Kelly Wood, a spokesman for agencies fighting the fire.

"The interior of the fire itself is going to burn until it burns itself out or until winter gets here and it rains or snows," said Wood, who traveled from Pinetop Fire Department in Arizona. "As for how long it could take, nobody knows."

Many of the fires have raged through areas not accessible by road. Helicopters dropped crews into remote areas to fight the 16 Complex blaze, two fires that began Sept. 4 near the Lake-Colusa border. Firefighters have become acquainted with the steep and rugged Rumsey Canyon, and the tactical challenges it poses, after several previous fires in the area.

Cal Fire investigators have not declared causes for any of the North Coast fires. Such investigations can take weeks or months.

"What we do are rule out other causes: Was there lightning that day? Is there a railroad nearby?" said Nicholls.

Lightning is the only natural cause, and it is rare. About 94 percent of fires handled by Cal Fire are caused by humans.

Equipment, from bulldozers to lawn mowers, are the most common cause, according to data collected over the past three years in Lake, Sonoma, Napa, Colusa and Solano counties, said Nicholls, who runs the Sonoma-Lake-Napa fire prevention bureau.

Burning debris and power lines are also common causes, followed less frequently by such things as spontaneous combustion of stockpiled materials, firearms, fireworks and children playing with flames.

Experts warn people to avoid using equipment during the hottest time of day or in windy conditions.

"A lot of fires are preventable," Nicholls said.

You can reach Staff WriterJulie Johnson at 521-5220 or julie.johnson@pressdemocrat.com.