'Miraculous': No casualties reported in devastating Colorado wildfires

Boulder County Sheriff Joe Pelle called the lack of casualties or fatalities "pretty miraculous" following the Colorado wildfires that quickly destroyed hundreds of homes on Thursday.

"We were fortunate that the winds dissipated last night," Pelle said in a press conference on Friday. "It's still too dangerous to return. We saw active fires in many places this morning. We saw downed power lines; we saw a lot of risks that we're still trying to mitigate."

Hundreds of homes were destroyed and thousands were forced to evacuate in Boulder County on Thursday when wind-fueled grass fires exploded into infernos. The more dangerous of the two, the Marshall Fire, "ballooned" to approximately 1,600 acres, Pelle said in a Thursday briefing.

The cause of the fires is still being investigated. According to the Boulder County Office of Emergency Management, Xcel Energy Colorado found no downed wires in the ignition area despite initial reports.

President Joe Biden approved a disaster declaration for Colorado on Friday and federal funsing for those affected, according to a statement from the White House.

“Assistance can include grants for temporary housing and home repairs, low-cost loans to cover uninsured property losses, and other programs to help individuals and business owners recover from the effects of the disaster,” the White House announced in the release.

“Federal funding is also available to State and eligible local governments and certain private nonprofit organizations on a cost-sharing basis for emergency work in the Boulder County.”

There were more than 2,000 homes in the affected area. About 500 homes have been lost to the blaze so far, but that total could rise to roughly 1,000 with further assessments, according to Pelle.

Residents of Louisville, a town of 20,000, and Superior, a town of 13,000, were alerted to evacuate immediately on Thursday.

The mayor of Superior, which was decimated by the sudden and fast-moving wildfires, called the situation "very grave" in an interview with "Good Morning America."

"I spent a couple of hours yesterday driving around in the afternoon with the sheriff’s office and town manager just making an assessment of the situation there on the ground and it’s grave," Superior Mayor Clint Folsom told "GMA." "It’s nothing like I would have ever imagined would have happened."

Folsom said he was fearful of what emergency responders might find in the coming days after hundreds of homes burned "in a matter of minutes."

Pelle and Colorado Gov. Jared Polis said some families in Louisville and Superior had little time to prepare to leave their homes in what the National Weather Service's Denver/Boulder bureau called a "life-threatening" situation.

"In the blink of an eye, this was a disaster in fast motion," Polis said at a press conference. "All over the course of half a day. Nearly all the damage. Many families having minutes to get whatever they could, their pets, their kids into the car and leave. The last 24 hours have been devastating, truly unimaginable."

Folsom said that strong winds were not uncommon in the area, but "this was a wind like I've never seen." Combined with an extraordinarily dry summer and fall, the conditions were ripe for a devastating blaze.

Several inches of snow are anticipated Friday, which could help efforts, Pelle said.

"We might have our very own New Year's Miracle on our hands if it holds up that there was no loss of life," Polis said.

ABC News' Molly Nagle contributed to this report.