As wet spring fades, North Bay’s tall grass poses severe wildfire threat

Rippling in the wind, waist-high green and brown grasses surrounded Michelle Halbur on a slope at Pepperwood Preserve in the Mayacamas Mountains north of Santa Rosa.

“I feel like I’m in the ocean,” the preserve ecologist said as she documented the resurgence of grasses, up to more than 5 feet tall, in an area blackened by a controlled burn a year ago.

But where Halbur marvels at fertile hillside, uneasy North Bay residents and firefighters now face a bumper crop of wild grass - fostered by drought-squelching rains - that threaten to fuel another disastrous season of wildfires in California.

Winter’s liquid largesse, which banished the five-year drought in California, turns to a liability as temperatures rise and - as the late Kate Wolf, a former Sonoma County resident, sang - “the hills turn brown in the summertime.”

Already statewide, more than 1,100 fires since the start of the year have burned more than double the swath of territory torched last year at this time, according to Cal Fire. In Sonoma County, a small wildland blaze last month caught the attention of local firefighters, who saw it as a potential harbinger of a bad season.

Windblown embers from a house fire east of Cloverdale crossed a road and ignited the grass on May 24, charring 5 acres before firefighters corralled the flames.

“It shows you the potential is there,” Cloverdale Fire Battalion Chief Rick Blackmon said. “Two or three months from now, it would have been a whole different story. The hills are starting to dry up.”

Most fires start in grass, known to firefighters as a “fine fuel” because it readily ignites and spreads flames quickly. Thicker grass burns hotter, becoming harder for firefighters to put out and increasing the chance of ground-level flames climbing into treetops and triggering a forest fire.

Pepperwood was scorched by the Hanly fire that roared from Calistoga to the edge of Santa Rosa in 1964, still Sonoma County’s largest fire. Today the preserve, dedicated to conservation science, protects 900 acres of grasslands with selective cattle grazing and controlled burns, while thinning its oak and fir woodlands.

But in recent years, Sonoma’s wildfire experience pales compared to southern Lake County, where a trio of fires in the summer and fall of 2015 wreaked havoc over 267 square miles - about one-fifth of the county’s land.

In the past five years, 24 Lake County wildfires have covered nearly 190,000 acres, while cooler, foggier Sonoma County had just six fires covering 5,500 acres, according to Cal Fire records for blazes of 10 acres or more from 2012-16.

The National Interagency Fire Center based in Boise, Idaho, noted last week that California’s “robust fine fuel crop” is drying now and will be “fully cured” by late July or August, elevating the threat of large grass and brush fires.

But concerns are already rising as fires are breaking out, mostly in the Central Valley and Southland, at a torrid pace this year.

Cal Fire’s latest tally counts 1,142 fires that have covered 15,406 acres since Jan. 1 in areas under the state agency’s jurisdiction, more than twice the swath of the 981 wildfires over 6,286 acres in the same period of 2016 and well above the five-year average of 11,046 acres.

There were 221 new fires in the past week, Cal Fire Deputy Chief Scott McLean said, noting that a San Diego County fire blackened 2,000 acres in late May and a small Butte County fire last week reached into tall timber.

“The public cannot be complacent,” he said.

Lake County got that message from the horrific Valley fire, which erupted in September 2015 and scorched 76,000 acres, took at least four lives and consumed nearly 1,300 homes, including 70 in Hidden Valley Lake. Losses totaled $1.5 billion from the third most destructive blaze in state history.

“We’re trying to be as prepared as we can,” said Phil Bayles, a retired U.S. Forest Service official who lives in the 3,300-home Hidden Valley Lake subdivision east of Highway 29 between Middletown and Lower Lake.

Property owner assessments are paying for six emergency sirens to be installed atop telephone poles around the subdivision this summer, he said. In the event of an approaching fire, the sirens would be triggered, giving “everybody an equal chance to get out of here,” Bayles said.

Hidden Valley Lake’s roughly 6,000 residents were caught in a bottleneck during the Valley fire as all roads leading from the subdivision empty onto the highway, which officials limited to one-way traffic, he said.

The subdivision also has a June 15 deadline for mowing lawns and clearing vegetation from common areas, the latter chore assigned partly to sheep.

A Cal Fire grant of nearly $109,000 is paying for a 9-mile, 300-foot-wide fire break ringing the Clearlake Riviera area of about 1,540 homes. The area did not burn last year or in 2015, but is vulnerable to fire because of winds off Clear Lake and its location at the base of Mount Konocti, said Mike Wilson, a longtime Cal Fire official who retired Friday as division chief of agency’s vegetation management program.

Bulldozers, brush mowers and hand crews are cutting the firebreak, which is about halfway completed, he said.

In Sonoma County, an 18-acre controlled burn Tuesday at Bouverie Preserve near Glen Ellen showed the grass is not yet critically dry. Fire behavior was slow moving and “relatively benign,” Cal Fire Battalion Chief Kirk van Wormer said.

But thick dry grass ultimately complicates firefighting, he said. “It’s harder to extinguish. We have to go slower to make sure the water reaches the ground.”

Fuel is not the only factor influencing wildfire ferocity, as temperature, humidity, topography and especially wind make the difference between a blaze that can be halted versus a monster that roars out of human control.

Southern California’s strong, dry Santa Ana winds blowing in from the desert are the reason why many of the state’s largest fires occur there. The explosive growth of the Valley fire in 2015 was also fueled by strong, dry winds.

Fire has always been part of the state’s landscape, and Cal Fire veterans say abundant grass is also nothing new.

Human behavior is the real X-factor, they say.

Most fires not only start in grass, but are ignited by human error, Cal Fire Battalion Chief Marshall Turbeville said. Common causes include cutting grass in hot weather, sparks from a grinder or a metal part dragging from a vehicle, embers from a burn pile or campfire, discarded fireplace and barbecue ashes and carelessly tossed cigarettes.

“Really, the difference is how careful people are during the fire season,” Wilson said.

You can reach Staff Writer Guy Kovner at 707-521-5457 or guy.kovner@pressdemocrat.com. On Twitter @guykovner.