Tinderbox-dry conditions during one of the driest summers on record resulted in the biggest wildfire to ever burn in the White River National Forest that surrounds Glenwood Springs, eventually consuming 32,631 acres.

The Grizzly Creek Fire sparked in the median along Interstate 70 in Glenwood Canyon just west of the Grizzly Creek rest/recreation area around 1:30 p.m. Aug. 10. It quickly spread beneath the elevated westbound lanes and up the north canyon wall.

Fire investigators later ruled the fire was human-caused from passing interstate traffic, but an exact ignition source was never determined.

Within 20 minutes, a huge plume of smoke was visible from Glenwood Springs and across the region.

Due to the fire’s impact on the major east-west thoroughfare, the Grizzly Creek Fire early on was declared the top priority for firefighting resources in the entire United States, as wildfires burned across much of the West.

As the fire blew up, rafters and hikers were quickly evacuated from popular areas such as Hanging Lake Trail and the Grizzly and Shoshone boat launches.

The interstate was immediately closed to all but emergency vehicle traffic — a closure that would remain in place for two weeks, as interstate traffic was detoured to the north via U.S. 40 and south via U.S. 50.

It was the longest closure of I-70 in Glenwood Canyon in the history of the interstate highway — a troubled stretch of road that’s prone to rockfall, slides and frequent accidents.

Restricted local routes over Cottonwood and Independence passes eventually had to be closed, though Independence Pass was reopened — after some political pressure from Garfield County — and controlled to prevent traffic snarls and illegal use by semi trucks.

For weeks, area firefighters had been busy putting out smaller brush fires around Glenwood Springs, and the massive lightning-caused Pine Gulch Fire in far western Colorado had been burning on BLM land since July 31 (eventually growing to 139,007 acres) before the Grizzly Creek Fire started.

The rugged, steep terrain of Glenwood Canyon prevented an effective initial attack, and it quickly grew out of control. The next day, it jumped I-70 and the Colorado River to the south side of the canyon, forcing evacuations of the No Name neighborhood and populated areas south on Lookout Mountain and east near Dotsero.

Incident command was established in Eagle County east of the fire, where access to the fire lines was easiest. The Grizzly Creek Fire soon surpassed the last large wildfire to burn locally, the 2018 Lake Christine Fire, which consumed 12,588 acres.

At its height, nearly 650 firefighting personnel under the direction of the Great Basin Incident Command Team and a battalion of aircraft and ground support battled the fire.

Incident command was handed over to the Alaska Type 1 Team on Aug. 25, a day after I-70 was finally reopened to traffic.

By then, the immediate threat of the Grizzly Creek Fire had subsided, though it burned well into the fall months.

No homes were lost and no deaths or serious injuries resulted. The fire was only officially declared 100% contained on Dec. 18, after the seasonal snows finally came.

jstroud@postindependent.com