3 people missing, nearly 1K structures scorched in Colorado wildfire, officials say

Authorities say three people are believed to be missing after a wind-fueled wildfire scorched about 6,000 acres and destroyed hundreds of homes and businesses in towns north of Denver on Thursday.

"Unfortunately we believe these are going to turn into recovery cases," Boulder County Sheriff Joe Pelle said at a news briefing Saturday. 

Pelle did not provide additional information about the missing people.

The news comes after authorities have repeatedly expressed amazement that the fire did not result in more injuries. At least seven people were injured, but no fatalities have yet been reported.

"We’re very fortunate we don’t have a list of 100 missing," Pelle said Saturday.

Pelle said cadaver dogs would be brought in starting Sunday to try to locate the missing people, who are feared dead. He said weather conditions were hindering the ability to search and recover bodies.

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'ABSOLUTELY DEVASTATING':Wind-driven Colorado wildfires burn hundreds of homes near Boulder

The Marshall Fire blanketed the Denver suburbs of Superior and Louisville in smoke Thursday and forced tens of thousands of people to flee. A total of 991 homes were destroyed, Pelle said. An additional 127 were damaged by fire. The cause of the blaze was under investigation.

Colorado Gov. Jared Polis called it "a disaster in fast motion," as most of the damage took place in just half a day. He declared a state of emergency to allow the state to access emergency funds and services.

On Saturday, President Joe Biden approved a major disaster declaration for the state, the Federal Emergency Management Agency announced. The declaration supplements state and local recovery efforts in the areas affected by the wildfires and straight-line winds.

Overnight snowfall was complicating recovery efforts Saturday. At least 6 inches of snow covered the area, where National Guard troops blocked off empty streets and Red Cross shelter volunteers distributed electric space heaters. Utility crews were struggling to restore natural gas and electricity.

The town of Superior shut off water in the burn areas Saturday to restore water pressure and prevent pipes from freezing, the Boulder Office of Emergency Management said on Twitter.

"Emergency response teams and utility providers are working hard in areas impacted by the fire to protect affected homes from further damage," the office said.

Meanwhile, mail carriers from across Colorado were expected to converge on Louisville Sunday to deliver mail "to the homes that are standing," United States Postal Service spokesperson David Rupert told USA TODAY.

Louisville and Superior, neighboring towns about 20 miles northwest of Denver, have a combined population of 34,000. The area is between Denver and Boulder.

Contributing: Trevor Hughes, Doyle Rice and Christal Hayes; Molly Bohannon, USA TODAY Network; The Associated Press