FOLLOW THURSDAY UPDATES:Another warm day forecast as crews continue to fight Elk Fire.

UPDATE 10:30 p.m.: All Glacier View gates from 7-13 are under mandatory evacuation, according to LCSO.

UPDATE 10 p.m.: The overnight evacuation center has moved to the Livermore Church, 284 W. CR 74E.

ORIGINAL STORY: The Larimer County Sheriff's Office has issued mandatory evacuations to residents and businesses in the Glacier View area due to "immediate and imminent" wildfire danger after a prescribed burn went out of control.

Larimer County Sheriff's Office spokesman David Moore confirmed that a planned 505-acre prescribed burn Wednesday at the Ben Delatour Scout Ranch west of the Glacier View subdivision "has now become a wildfire."

An estimated 50 homes on North Rim Road were threatened by the blaze as of 6:40 p.m., Moore said. There has been no damage to primary residences.

This story has been made free for everyone to view due to public safety concerns. To support the work of the Coloradoan and to ensure we can keep providing this service in the future, subscribe today.

The Elk Fire is estimated at 175 acres with 10% containment. More than 70 firefighters and 10 engines are on scene with more en route according to LCSO. Air resources, including a heavy air tanker, are also on scene with a primary goal of dropping retardant around homes, Moore said.

Moore said no further updates were expected Wednesday night. Firefighters will be on scene overnight and "hit hard again in the morning," he said.

According to an emergency alert, overnight power outages in the area are possible. Poudre Valley REA shut down power on North Rim Road due to some poles being compromised, Moore said.

Residents are encouraged to sign up for text updates by texting the word LCEVAC to 888777 from your cell phone. Residents can also get information at the overnight evacuation shelter.

The fire's general boundaries are south of 74E, north of Elkhorn Creek and west of Rim Road, Moore said.

The evacuation area is "roughly south of CR 74E and north of Rim Road between CR 68C on the west and Walkabout Road (Glacier View Gate 5)," the sheriff's office tweeted.

Gates 1,3, 5 and 6 in Glacier View are under voluntary evacuation. Gates 7-13 are under mandatory evacuation.

A reverse 911 alert sent just before 5 p.m. to 904 devices, asked everyone in the area to evacuate immediately and as quickly as possible.

"Do not delay leaving to gather belongings or make efforts to protect your home or business," the alert said.

Livermore Fire Chief Donn Maynard told the Coloradoan the wind shifted at 3:34 p.m., causing the prescribed burn to go out of control. Maynard said the fire is expected to burn several days, but he was hopeful the wind dying down after sunset Wednesday would aid in firefighting efforts.

Weather conditions in the area as of about 7 p.m. Wednesday were 54 degrees with west and southwest winds at 11 mph with 17% humidity.

Maynard said Red Feather Lakes and Crystal Lakes are not effected.

The only confirmed structure lost is a shed on North Rim Road, Maynard said, adding that firefighters have saved at least one house in the burn area.

As of about 6:10 p.m. Wednesday, about 30 cars were at the original evacuation center at the Livermore Community Center. At least five dogs and one cat were in the evacuation center Wednesday, with more animals in the parking area.

Those at the community center hugged as they reunited. One evacuee called and asked The Forks Restaurant to send evacuees pizza — and the restaurant delivered.

Some evacuees said they are more prepared for wildfires because of the 2012 High Park Fire, which burned more than 87,000 acres over three weeks.

One, Kim Kohler, told the Coloradoan her husband could see High Park's flames from their current home. Her husband went back home Wednesday night to grab supplies for them, she said.

"It's nerve-wracking," Kohler said. "I even had a gut feeling today was a bad day to continue the (prescribed) burns."

American Red Cross is helping book evacuees into hotel rooms.

As they awaited word on what would come next, evacuees gathered around Maynard's radio for updates.

After arriving at the evacuation center Wednesday night, Moore told about 40 evacuees that dropping temperatures are aiding firefighting efforts and a fire weather watch for Thursday has been cancelled.

The Nature Conservancy burn "is part of the larger Elkhorn Creek Forest Health Initiative to improve forest health and protect the Elkhorn Creek and Cache la Poudre watershed with previous forest and prescribed fire treatments having occurred in the area," according to an LCSO Facebook post.

In addition to LCSO, Glacier View, Red Feather Lakes, Livermore, Crystal Lakes, Poudre Canyon, Poudre Fire Authority and Wellington fire departments are responding as well as U.S. Forest Service and The Nature Conservancy. Air resources are en route, Moore said.

Authorities are asking residents not to call 911 unless you are in danger.

Another prescribed burn more than 10 miles away from the wildfire went as planned, U.S. Forest Service's Reghan Cloudman said in an email. The forest service staffed that burn, located north of Red Feather Lakes, with approximately twice the number of firefighters required by the agency's burn plan, Cloudman wrote, adding that "all conditions were within the acceptable range, including weather and fuel moisture."

This story has a correction: Due to incorrect information posted by authorities, the gates under mandatory evacuation were not correct in a previous version of this story. The story has been updated with corrected information from LCSO.

Coloradoan reporter Miles Blumhardt contributed to this report.

This is a breaking news story and it will be updated as more information is available.