The 416 Fire is on track this week to become Colorado's fifth largest wildfire in history, which would place the burn north of Durango behind the state's fourth largest wildfire: the Missionary Ridge Fire in 2002.
According to a Monday morning update from the National Incident Management Organization, the 416 Fire grew by 1,767 acres Sunday, bringing the total area burned to 51,068 acres.
With no signs of slowing down, the 416 Fire is set to break the top five largest wildfires in Colorado state history. Currently, the Last Chance Fire that burned 52,000 acres in 2012 in eastern Colorado holds that spot.
The Missionary Ridge Fire ripped through 71,739 acres, north of Vallecito.
As of Monday afternoon, the Spring Fire in Costillo County jumped ahead of the 416 Fire in terms of total area burned, scorching more than 56,000 acres.
The Colorado State Forest Service, which tracks these numbers, does not add fires to its list until the burns are fully contained.
Julie Malingowski, a meteorologist with the National Weather Service in Grand Junction, said weather conditions this week will continue to be hot and dry, creating continued risk of fire danger and fire spread.
"Temperatures are expected to rise gently over this week into the weekend," she said.
There is a chance for some isolated thunderstorms Tuesday in the San Juan Mountains, but not a lot of precipitation is expected with the storm. Though the storm's not predicted to be widespread, it does carry the risk of lightning strikes.
The next possible chance for rainfall is Friday and into the weekend, when a tropical storm off the coast of the Pacific Ocean may bring moisture to Southwest Colorado.
"There'll be an increased chance for afternoon showers throughout the weekend," Malingowski said.
Still, the much-needed rainfall this weekend is not the start of the monsoon pattern fire experts say is the only real chance to extinguish the 416 Fire, as well as the Burro Fire further west.
"We are not there yet," Malingowski said.
Over the weekend, however, weather conditions allowed for significant progress on the 416 Fire, according to the Monday report, with firefighters finishing burnout operations on the fire's southwestern edge.
Crews will remain holding the fire line west of Forest Road 171 to Sheep Head Basin, southeast of the Hermosa Creek wilderness area, with the assistance of helicopter water drops.
With burnout operations concluded, firefighters have moved to the north edge of the fire in an effort to strengthen existing fire lines and prepare for future burnout operations to protect Purgatory Resort.
Purgatory Resort announced the reopening of summer activities on Sunday. Fire officials said visitors should check location conditions when planning trips and activities to areas around the fire.
County Road 124 from the junction of County Road 124A will be closed starting Monday, restricting access to Kennebec Pass trailhead.
San Juan Basin Public Health on Monday issued an air-quality health advisory throughout La Plata County, as well as areas of Hinsdale, Montezuma and San Juan counties.
Heavy smoke settled along the Animas River from north Durango down to the New Mexico state line, the health department said. The smoke is expected to linger overnight, and clear around noon Tuesday.
Areas around Purgatory Resort on Monday afternoon are expected to reach moderate to unhealthy levels for sensitive groups, such as children and seniors.
To date, the 416 Fire, which started June 1, has cost $27 million to fight. As of Monday morning, the fire was 37 percent contained. The cause of the fire is still listed as "under investigation."
jromeo@durangoherald.com