Blackened fingers of charred wood, twisted metal deck railings, and a building’s worth of burned fire debris are all that’s left of a 45-year-old, two-story, octagon-shaped structure that used to house the Don Pedro Recreation Agency headquarters and visitor center.

The cause of the fast-moving blaze that burned the reservoir’s recreation nerve center to the ground Wednesday night remained under wraps Thursday. Firefighters, Turlock Irrigation District staff and utility personnel were on scene near the hillside 6-acre burn where the building used to overlook Don Pedro Powerhouse below Don Pedro Dam.

Don Pedro Recreation Agency, a partnership sponsored by Turlock ID, Modesto Irrigation District and the City and County of San Francisco, has nothing whatsoever to do with monitoring, operation and security of Don Pedro Reservoir, Don Pedro Dam and Don Pedro Powerhouse.

Reservoir, dam and powerhouse operations were not impacted, Turlock Irrigation District spokesman Calvin Curtin said Thursday outside the fenced-off, taped-off burn area.

Burn closed

The area is expected to remain closed to the public until the middle of next week for ongoing investigations by Tuolumne County Fire, Cal Fire and insurance representatives.

A trailer was set up Thursday to act as a temporary visitors center for the coming Memorial Day weekend, when as many as 10,000 visitors are expected over four days.

Curtin said a Turlock ID employee, Ranger Brannon Gomes, was first to hear of the fire, via an alarm system. Gomes is among staff who live near the recreation headquarters, in staff housing on the opposite side of Don Pedro Dam.

Gomes went to the building, realized there was a fire inside and attempted to put it out with a hose, Curtin said.

“He tried to knock it down but realized it was too big and called 911,” Curtin said.

The fire was reported at 9:35 p.m. as a commercial structure fire in the 10200 block of Bonds Flat Road, said Cal Fire Capt. Chris Morse of the agency’s San Andreas emergency command center.

The first dispatch was at 9:36 p.m., the nearest Cal Fire personnel responded from the Blanchard Station on Highway 132 in La Grange, and they arrived on scene at 9:43 p.m., Morse said Thursday.

The entire building was fully involved in flames by that time, and the blaze spread downslope to burn about 6 acres of grass and brush below, Morse said.

Fire engines, trucks, water tankers and a bulldozer responded from agencies including Cal Fire, Tuolumne County, Mariposa County and Sonora. Resources included at least seven engines and two hand crews. No injuries were reported.

Under wraps

The Don Pedro Recreation Agency building, which featured wrap-around decks on the second floor and views of the dam and powerhouse, was a total loss, Curtin said. It was built in 1971, the same year New Don Pedro Dam was completed to replace a concrete dam built in 1924.

No estimates for the building and total property loss were available Thursday afternoon. Curtin said the building was insured.

The cause was under investigation Thursday. Both Turlock ID staff and Cal Fire personnel agreed the fire appeared to originate inside the building.

Curtin and Morse gave similar accounts: the first people on scene, an employee and firefighters, said the fire appeared to be inside the building and not yet burning in vegetation.

The Don Pedro Recreation Agency headquarters and visitors center housed all the agency’s documents as well as irreplaceable cultural artifacts, including Native American arrowheads and Gold Rush-era mining tools.

Also destroyed were photographs of the first and only time Don Pedro Dam operators opened the reservoir spillway in January 1997.

‘Unique architecture’

Don Pedro Recreation Agency officials considered their headquarters building a gem worth boasting about. The following description of the building and its grounds appears on a Don Pedro Recreation webpage:

“With its unique round architecture overlooking Don Pedro Dam and reservoir, the Don Pedro Recreation Agency Visitor Center offers a stunning view of the Yosemite back-country peaks of Mt. McClure, Mt. Lyell, Mt. Florence and Mt. Clark.

“Interpretive exhibits highlighting the Don Pedro Recreation Area, the local area history, construction of the reservoir and dams along the Tuolumne River watershed and the flora and fauna of the area are housed by the building.

“Spring wildflower displays as viewed from the visitor center are exceptional, with the face of the dam covered with lupine and the surrounding hills covered in hues of yellow, white, purple and blue. The habitat around the visitor center attracts wildlife year around. Bald and golden eagles, osprey, red tail hawks and other raptors, waterfowl, a large variety of songbirds, deer, bobcat, coyote and many other native California foothill wildlife inhabitants are common visitors to the area around the facility.

“Picnic tables and benches outside of the visitor center offer a chance to rest and enjoy the scenery.”

The picnic tables are still there, but they are close to the burn in a fenced-off area that remains closed.

Curtin said he expects the impact of Wednesday night’s fire will be minimal for visitors. He emphasized the fire Wednesday night had no effects on recreation opportunities at the reservoir, including campsites, boat launch ramps and marinas.

Don Pedro Reservoir was holding 1.52 million acre feet of water as of Thursday. That means the man-made lake that impounds Tuolumne River waters is about three-quarters full. Curtin said the reservoir is about 98 of normal capacity for this time of year, and the water surface, at 786.5 feet above sea level, is the best seen at Don Pedro since 2010-2011.