Hundreds of firefighters in Utah have struggled to suppress a wildfire that scorched an additional 20,000 acres (8,000 hectares) as of Saturday, as low humidity and strong winds accelerated the fire spread, according to state officials.

The Cottonwood fire erupted on Monday in the Fishlake national forest, located in central Utah. The blaze intensified overnight, growing from about 70,000 acres (28,000 hectares) to more than 92,000 acres (37,000 hectares) on Saturday morning, according to the US Forest Service. The fire is at a 0% containment level and is the largest blaze currently burning in the US, according to the National Interagency Fire Center.

There have been no reported injuries or casualties. So far, the fire, whose cause remains under investigation, has left property damage at a ski resort in Beaver county and led to the closure of the national forest.

Authorities expect slightly improved weather conditions on Saturday, but they warned that the afternoon may bring “extreme fire behavior” once more due to an increase in temperatures and wind speeds.

Residents living north-east of the fire, including in the small town of Marysvale, have been cautioned about “unhealthy” air quality conditions from the blaze’s smoke.

Utah is experiencing an unprecedented wildfire season. Two fires burning near Eureka, a town about 80 miles (130km) south of Salt Lake City, have consumed about 70,000 acres combined, prompting residents to evacuate.

The National Weather Service in Salt Lake City issued a rare red flag warning on Thursday related to the Cottonwood fire, indicating a high risk of rapid fire spread and life-threatening conditions.

Utah’s governor, Spencer Cox, implemented temporary restrictions on firework use statewide ahead of the Fourth of July, which will mark the 250th anniversary of American independence.

“This is unlike anything we’ve seen in recent memory,” said Jamie Barnes, director of the Utah division of forestry, fire and state lands, in a Thursday news release, after the firework moratorium was announced.

“We’re seeing fires spread farther and faster under conditions that defy historical expectations. Some of the fires we’ve responded to this year are behaving in ways veteran firefighters simply haven’t seen before. Our firefighters have been working around the clock, our resources are stretched, and we cannot afford preventable ignitions during the days ahead,” she added.

Utah has had 380 fires this year, according to a state government dashboard. Humans were responsible for 273 of them.