SUPERIOR – A Colorado official says nearly 1,000 homes were destroyed, hundreds more were damaged, and that three people are missing after a wildfire charred numerous neighborhoods in a suburban area at the base of the Rocky Mountains northwest of Denver.

Boulder County Sheriff Joe Pelle also said Saturday that investigators are still trying to find the cause of the blaze that erupted Thursday. Officials had previously estimated that at least 500 homes – and possibly 1,000 – were destroyed. They also announced earlier Saturday that two people were missing.

The wind-whipped wildfire blackened entire neighborhoods in the area between Denver and Boulder.

Authorities had said earlier no one was missing in the area hit by Thursday’s blaze, but Boulder County spokeswoman Jennifer Churchill said Saturday that was because of confusion inherent when agencies are scrambling to manage an emergency.

Pelle said officials were organizing cadaver teams to search for the missing in the Superior area and in unincorporated Boulder County. The task is complicated by debris from destroyed structures, covered by 8 inches of snow dumped by a storm overnight, he said.

At least 991 homes were destroyed, Pelli said: 553 in Louisville, 332 in Superior and 106 in unincorporated parts of the county. He cautioned that the tally is not final.

The cause of the blaze was under investigation. Pelle said utility officials found no downed power lines around where the fire broke out. He said authorities were pursuing a number of tips and had executed a search warrant at “one particular location.” He declined to give details.

The news came as an overnight dumping of snow and frigid temperatures Saturday compounded the misery of hundreds of Colorado residents who started off the new year trying to salvage what remains of their homes.

At least 6 inches of snow and temperatures in the single digits cast an eerie scene amid the still-smoldering remains of homes. Despite the shocking change in weather, the smell of smoke still permeated empty streets blocked off by National Guard troops in Humvees.

For the thousands of residents whose homes survived the conflagration, Red Cross shelter volunteers distributed electric space heaters as utility crews struggled to restore natural gas and electricity.

At least seven people were injured in the wildfire that erupted in and around Louisville and Superior, neighboring towns about 20 miles northwest of Denver with a combined population of 34,000. More than 500 homes were feared destroyed.

The blaze, which burned at least 9.4 square miles, was no longer considered an immediate threat.

Families forced to flee the flames with little warning began returning to their neighborhoods Friday to find a patchwork of devastation. On some blocks, homes reduced to smoking ruins stood next to ones practically unscathed by the fires.

As the flames swept over drought-stricken neighborhoods with alarming speed, propelled by guests up to 105 mph, tens of thousands were ordered to flee.

With some roads still closed, people walked back to their homes to get clothes or medicine, turn the water off to prevent the pipes from freezing, or see if they still had a house. They left carrying backpacks and pulling suitcases or wagons down the sidewalk.

President Joe Biden on Friday declared a major disaster in the area, ordering federal aid be made available to those affected.

The wildfire broke out unusually late in the year, following an extremely dry fall and amid a winter nearly devoid of snow until the overnight snowfall.

Superior and Louisville are filled with middle- and upper-middle-class subdivisions with shopping centers, parks and schools. The area is between Denver and Boulder, home to the University of Colorado.

Scientists say climate change is making weather more extreme and wildfires more frequent and destructive.

Ninety percent of Boulder County is in severe or extreme drought, and it hadn’t seen substantial rainfall since mid-summer. Denver set a record for consecutive days without snow before it got a small storm on Dec. 10, its last snowfall before the wildfires broke out.

Associated Press writers Thomas Peipert in Louisville, Thalia Beaty in New York and Brady McCombs in Salt Lake City contributed to this report.