The Cottonwood Flat Fire Melted a FlexSteel Gas Line

A FlexSteel gas line melted and ignited on July 17, 2025, inside the Cottonwood Flat Fire between Parachute and Rulison. The brush fire ran from about 2 acres to 310 acres that afternoon, closed U.S. Highway 6 until 10:20 p.m., and left Interstate 70 open.

Twenty-one days earlier, the Hilltop Fire had already burned the junction of County Road 309 and County Road 320, destroyed a house, a mobile home, a shed and an RV, and pushed 20 to 25 households out. The second fire on that road looked smaller on a map. On the slope it hit a live gas line.

From 2 Acres to 310 Before Dark

Garfield County Sheriff’s Office Public Information Officer Walt Stowe said deputies were dispatched around 2:40 p.m. Thursday, July 17, 2025, to a 1- to 2-acre fire in heavy brush just off Interstate 70 near mile marker 79. Upper Colorado River Interagency Central Zone crews logged the same start as Initial Attack 227 at 1445 hours in Cottonwood Flats, a steep run of grass and brush above Rulison, a small Garfield County oilfield community.

By 4:38 p.m. the sheriff’s office had ordered people off County Road 309 from the Rulison-Parachute Road to the main Rulison exit at mile marker 81. Anyone within a one-mile radius of 1800 County Road 309 was told to leave. A two-mile ring sat on pre-evacuation. Livestock could go to Cottonwood Park Rodeo Grounds at 100 La Plata Circle in Parachute. Dispatch lines were so busy by Friday morning that the county asked people to stop calling for updates.

The National Interagency Fire Center put the fire at about 310 acres by Thursday evening, and that number did not grow. Colorado River Fire Rescue led the suppression with help from other agencies. Air tankers and helicopters were brought in as the fire made its first run. A Grand Valley Fire spokesperson said Sunday, “There’s been no new growth. We’re doing good.”

THE COTTONWOOD FLAT WEEK

1. July 17, 2025, 2:40 p.m.: Deputies respond to a 1- to 2-acre brush fire near Interstate 70 mile marker 79.
2. July 17, 4:38 p.m.: Mandatory evacuation covers County Road 309 to the Rulison exit and homes within one mile of 1800 County Road 309.
3. July 17, 10:20 p.m.: Highway 6 reopens both ways between mile markers 77 and 83. Interstate 70 never closes.
4. July 18, 5 p.m.: The fire holds at 310 acres. Evacuated residents may return. County Road 309 drops to pre-evacuation and stays closed to the public.
5. July 20: Grand Valley Fire Protection District estimates 35 percent contained, with about 100 people on the line and no new growth.
6. July 21: The National Interagency Fire Center lists 65 percent contained.
7. July 22, 4 p.m.: Grand Valley Fire declares the fire 100 percent contained and lifts pre-evacuation orders.

Federal wildfire records later listed the cause as natural. During the burn, Stowe said investigators had not named one.

The FlexSteel Pipe That Failed at 185 Degrees

The acres stopped growing Thursday night. The hazard that stayed with the crews was underground only in theory. Two above-ground natural gas lines sat near the heel of the fire, one steel and one FlexSteel. Local firefighters and oilfield workers told after-action writers that most gas lines in that country are buried. These two were not.

Most of the wells and pipe sat on the northwest flank, where the fire backed and flanked at lower intensity. The east side, the left flank, took the growth. The FlexSteel line still got hot enough to fail. Those pipes are common in petroleum service and have a strong field record, but the jacket is built for a maximum of 185 degrees Fahrenheit. The passing front went past that. The outer polyurethane melted, the steel core sat in the open, gas leaked, and the leak lit.

Once this pipe was exposed to the high temperatures of the passing wildfire, the outer polyurethane melted away, exposing the steel middle section. This resulted in a natural gas leak and subsequent gas line fire.

Rapid Lesson Sharing note, Wildland Fire Lessons Learned Center

The same note says the FlexSteel pipe ruptured under wildfire heat and threw a high-pressure, gas-fueled fire on a slope already stacked with wells. Surface pipe can sit in overgrown brush, sit poorly marked, and run along the same roads engines use. When it burns it can throw fumes, and the product inside can be flammable, toxic, or both.

WHAT THE PIPE FAILURE TAUGHT CREWS

• Find it first: Surface pipe hides in brush and may be unmarked, and a lot of it runs beside roads where engines and tenders pass.
• Treat the product as live: The line can be under high pressure and can carry flammable gas, poison, or liquids that make a second fire of their own.
• Leave the gas fire: Briefings say to tell the incident commander, pull in resource advisors and oilfield staff, close the ground, disengage and never fight a gas-line fire.

That is a different job from scraping line in oak brush. The people who had to make that call were not the drivers stuck on a taped-off frontage road. They were the engines and oilfield techs standing on a slope that had already proven it could take a house, three weeks earlier, a few miles of the same dirt.

Why Highway 6 Closed When I-70 Did Not

U.S. Highway 6 is the old valley road that still stitches Parachute to Rulison along the Colorado River. Interstate 70 runs a few hundred yards north of it through the same cut. The fire burned south of the interstate on County Road 309, so the local highway took the closure and the interstate did not.

Garfield County’s timed alerts that reopened Highway 6 at 10:20 p.m. Thursday, both directions, mile markers 77 to 83. Stowe had already said Interstate 70 was staying open, even with smoke sitting over the Grand Valley. For through traffic that was a delay, not a cutoff. For people who live on County Road 309 it was the difference between a frontage-road detour and a dead end.

After the mandatory order lifted, the county still ran the dirt road like a split driveway. Residents east of mile marker 4 were told to come in from the Rulison exit. Residents west of mile marker 1.9 were told to come in from Parachute, later spelled out as addresses above 4000 via Rulison and addresses below 1900 via Battlement Mesa. The road stayed closed to the public and open to people who lived there, so engines, tenders, and residents were sharing the same narrow grade.

The geography does that work on a quiet day. County Road 309 is the Rulison-Parachute Road, a local spine between the interstate and the benches where wells, ranch gates, and a thin line of houses sit. Close it, and the valley does not empty. It pinches. Interstate 70 can stay green on a traffic map while the people who actually use mile marker 79 are bouncing through a one-way plan written at 5:22 p.m. on a Friday.

County Road 309, Three Weeks After Hilltop

Hilltop started shortly before 3 p.m. on Thursday, June 26, 2025, near the intersection of County Road 320, the Rifle-Rulison Road, and County Road 309, southeast of Rulison. Colorado River Fire Rescue Chief Leif Sackett had it at 200 to 300 acres and 0 percent contained that first afternoon. Mapping later put it at 326 acres. Stowe said 20 to 25 homes were emptied, and a house, a mobile home, a shed, and an RV burned. The sheriff’s office called the cause under investigation and believed it was human and preventable. Containment was declared at 8 p.m. on Saturday, June 28.

Cottonwood Flat started on the same county road 21 days later, closer to the interstate, and never put a public number on lost houses. Federal fire-area records list 230 people and 103 housing units in the mapped vicinity, which is a buffer around the burn, not a headcount of who packed a bag. Parachute and Battlement Mesa were left off the evacuation list because the fire was moving east, away from those streets and toward Rulison.

TWO FIRES ON COUNTY ROAD 309

Two mid-size brush fires on one county road in three weeks is not a coincidence of weather so much as a description of the place. The benches south of Interstate 70 mix grass, two-foot brush, and timber understory with well pads and surface pipe. Hilltop showed what that mix does to houses. Cottonwood Flat showed what it does when the pipe is the thing that fails.

Ash Reached the Taps in Battlement Mesa

Battlement Mesa never went under a Cottonwood Flat evacuation order. Its water system still took the burn. Area notices put restrictions in place through July 20 after a large amount of ash and debris entered the system, which is a three-day problem for a community that was told it was on the safe side of the map.

That is the second quiet ledger on this fire. Highway 6 was open again before midnight Thursday. Mandatory evacuees on County Road 309 were told Friday afternoon they could go home, with a warning to be ready to leave again. Pre-evacuation hung on until Tuesday. The water rule outlived the highway tape and ran to the same Sunday when Grand Valley Fire was still quoting 35 percent contained.

Xcel Energy and other utilities came in behind the engines to repair damaged power lines, and officials said helicopters might help with that work. Lights, taps, and a dirt road with limited access are the parts of a 310-acre fire that never show up in a mile-marker closure. They sit with the metro district, the co-op, and whoever is still hauling stock back from 100 La Plata Circle.

Mop-Up Work Outlasted the Evacuation Orders

Grand Valley Fire Protection District posted at 4 p.m. on Tuesday, July 22, 2025, that the Cottonwood Flat Fire was 100 percent contained and that pre-evacuation orders were lifted. Crews stayed for mop-up and watch-outs. County Road 309 kept limited access, and drivers were asked to treat the grade as an active work zone.

Thank you to the residents and visitors for your patience, support, and cooperation throughout this incident. Your efforts to avoid the area helped ensure the safety and success of firefighting operations.

Grand Valley Fire Protection District, social media post

Federal wildfire incident records listed the estimated cost at $2.8 million and still showed the fire at 310 acres, 100 percent contained, when the file was updated on October 21, 2025. Primary fuel was logged as timber with grass and understory, with two-foot brush behind it. About 100 people had been assigned over the weekend of the burn. By the October update the standing organization had shrunk to a monitoring leftover.

AFTER CONTAINMENT

• The bill: Federal records put the estimated cost at $2.8 million for a fire that never grew past 310 acres after Thursday night.
• The lines: Xcel Energy and other utilities repaired damaged power lines, with helicopters on call for the work.
• The road: County Road 309 stayed on limited access after Tuesday so mop-up and line repair could finish.
• The water: Battlement Mesa’s system carried ash and debris restrictions through July 20, two days before full containment.

The lesson-sharing note on Fire 227 is dated with the burn, not with the highway closure. It treats Cottonwood Flats as oil-and-gas ground that crews already knew, a place where pipe ruptures during a fire had been rare, until the jacket on one FlexSteel line hit its 185-degree ceiling. Highway 6 was a Thursday problem. The pipe, the taps, and the second fire in 21 days on County Road 309 are what that week left on the slope.