CONIFER, Colo. (CBS4)– The wildfire burning in the mostly rural area southwest of Denver was 45 percent contained Thursday evening.

The Lower North Fork Fire has burned about six square miles. More than 650 firefighters continue to fight the blaze hoping to expand their containment line in case hot and windy weather returns this weekend.

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Thursday evening 180 homes remained evacuated and 7,000 homes were on standby for evacuation. Some of the evacuees were allowed to return home but with a warning: they should be ready to go home with little or no notice.

Those areas are Foxton Road to Reynolds Ranch Open Space Park, Pleasant Park Road as far as Critchell Road, High Grade Road and West Platte River Road. All other areas remain off limits to homeowners.

The fire was apparently sparked by a state-prescribed burn that was stirred up by strong winds on Monday. Since then, 27 homes have been damaged or destroyed, an elderly couple was found dead at one of the homes and a woman whose house was destroyed remains missing.

A computer problem may have caused some homeowners from being warned about the fire. Jefferson County confirms the Emergency Notification System never reached 12 percent of the residents.

“Seeing my home today, seeing everything gone, I mean there was nothing, nothing there to save,” said fire victim Coe Meyer. His home was destroyed in the fire.

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“And as I came out police and firefighters were there yelling at me, ‘Why are you still in there? That area was evacuated!’ No one knocked on my door, I did not get a reverse 911 call, I did not hear a siren or hear a speaker.”

FirstCall Network Inc. handles Jefferson County’s system that’s designed to automatically calls residents. Matthew Teague, the company’s president, told 4 On Your Side Investigator Rick Sallinger that there was not glitch and the system worked just fine.

Teague said the 12 percent who didn’t receive the calls either had their phone disconnected or they weren’t listed in the phone book.

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The Jefferson County Sheriff’s Office acknowledges there was a problem.

“Obviously there is some concern about our reverse 911 right now. That’s why we’re backing it up with a secondary plan of deputies in the area with sirens on in the event that we have to do another evacuation” said Jefferson Co. Sheriff spokeswoman Jacki Kelley.

If the fire blows up again the sheriff’s office will not rely on reverse 911 calls. Squad cars will be dispatched with sirens blaring.

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Those who do not have a fixed land line must sign up for reverse 911 calls. The website homeowners should register their phones to receive reverse 911 calls is