The Pine Gulch fire north of Grand Junction nearly doubled in size overnight for a second time, growing by almost 40,000 acres to become the second largest wildfire in state history.

The lightning-caused fire started July 31 and was at 125,252 acres Wednesday morning, according to the Rocky Mountain Area Coordination Center.

Its explosive growth places it behind only the 2002 Hayman fire, which burned 138,114 acres in Park, Teller, Douglas and Jefferson counties. Despite its size and ranking, the Pine Gulch fire has been far less destructive, burning in brushy, sparsely populated areas.

The Hayman fire, which was started by arson, caused six indirect fatalities, including five firefighters from Oregon who died in a traffic accident on their way to respond to the fire and a woman who suffered a fatal asthma attack from smoke inhalation.

Six hundred structures were lost — 133 residences, one commercial building, and 466 outbuildings — causing more than $42 million in housing losses. A total of 5,340 people were forced to evacuate.

What the Pine Gulch fire shares with the Hayman fire and three other major fires burning on the Western Slope, is its rapid, uncontrolled growth during extreme drought and weather, both attributed by many to climate change.

The fire grew more than 37,000 acres overnight as hot, dry, windy conditions persisted, said Larry Helmerick, with the coordination center.

Almost 900 firefighters on the ground and in the air are trying to increase containment which has held at 7% for more than a week.

Dried out pinyon, juniper, oak and sagebrush have been fueling the fire and no help is expected from the weather in the foreseeable future — excessive heat warnings have been issued for western Colorado with highs in triple digits predicted.

Grizzly Creek fire

Of the other major fires burning in Colorado, the Grizzly Creek fire east of Glenwood Springs has been the nation’s top firefighting priority because it has shut down Interstate 70 through Glenwood Canyon since it broke out Aug. 10.

On Wednesday, the fire was at 28,030 acres, with containment at 4%, the U.S. Forest Service said.

It was the first headway more than 800 firefighters assisted by 17 helicopters have been able to make in containing the blaze; previously containment had been at zero percent.

Roads and natural barriers helped firefighters in containing the fire, according to Mary Cernicek, spokeswoman for the Grizzly Creek fire. The fire’s pace also slowed in aspens, which Cernicek said burn slower than conifer trees.

But weather is still a concern for firefighters as dry lightning and strong winds are possible amid thunderstorms in the next few days. Thunderstorms pose significant danger because winds can quickly change the direction the fire is burning, she added.

Williams Fork fire

Burning in the Arapaho National Forest 15 miles southwest of Fraser, the Williams Fork fire was at 6,726 acres Wednesday with 3% containment, the Forest Service said.

Cameron Peak Fire

Northwest of Fort Collins, the Cameron Peak fire is at 15,738 acres and remains zero percent contained.

Winds from thunderstorms are expected to exacerbate the spread of its smoke and flames. Five-hundred firefighters are battling the blaze along with 10 helicopters. There are several road closures but no structures have been damaged.

Red Canyon fire

A fifth, much smaller fire broke out Wednesday afternoon south of Glenwood Springs and north of Carbondale, forcing some evacuations, according to the Carbondale & Rural Fire Protection District.

Initially reported at 20 acres, it had grown to about 30 or 40 acres later in the afternoon.