Rema Rahman, Associated Press

CONIFER, Colo. (AP) — Authorities said Friday that they were investigating problems with an emergency notification system because some residents who had signed up to get wildfire warnings never got one.

About 12 percent of people failed to get a warning about a wildfire in the mountains southwest of Denver on Monday. Jefferson County sheriff’s spokesman Mark Techmeyer said that some of those people likely hung up after hearing the pause that precedes the automated message or that their phone may have been busy.

He said that is bound to happen in any emergency but that authorities were most concerned there wasn’t any attempt to reach an unknown number of other people registered to get them.

“We want to get to the bottom of this as much as our citizens do,” Techmeyer said.

The company that handles the system, Baton Rouge, La.-based FirstCall Network Inc., has previously said the system worked exactly as it should have. President Matthew Teague said Thursday that reaching 88 percent of people in the middle of a weekday was a “great percentage.”

He was traveling Friday and didn’t immediately respond to the county’s claims about the failure to try to contact some people.

The calls went out in two waves, and the first wave included a number of people outside the evacuation area and some outside Colorado, Techmeyer said. He didn’t know the locations of the out-of-area phones that got calls, or the times of the two waves.

Sheriff’s officials said they were trying to get more data from FirstCall but said that may take a while and voiced frustration with the company.

Sheriff’s officials say a couple found dead in the fire zone got a call, as did a woman who remains missing but it wasn’t immediately clear when the calls came. A team has searched 219 acres for Ann Appel and planned to scour another 80 acres on Friday.

About 500 firefighters were working Friday to contain more of the 6-square-mile wildfire, which was apparently sparked by a state controlled burn that sprang to life because of strong winds. It has damaged or destroyed at least 25 homes, and crews have cleared lines around 45 percent of its 8.5-mile perimeter.

Wind gusts of over 25 mph were expected to return Saturday night but that’s not as bad as originally predicted.

“It’s going to be squirrely work. The good news is that’s tomorrow,” Techmeyer said.

Gov. John Hickenlooper has ordered a suspension on prescribed burns on state land and pledged a thorough review of the rules for such fires.

Residents of about 180 homes remain evacuated. At the height of the fire threat, residents of about 900 homes were to flee.

With so many people out of their homes most of the week, mail that couldn’t be delivered has piled up in one post office. But there are signs of life returning to normal, with power restored to some areas and the closure of an overnight shelter.

Friends and family of the couple who died, Sam Lamar Lucas, 77, and Linda M. Lucas, 76, planned a memorial service on Friday at their church.

While residents raised concerns about the phone notification system, Pueblo County emergency managers said they have used their system without major problems. Those instances, however, generally involve less than 100 calls, said Tim Nawrocki, communications manager for the county Office of Emergency Management.

“It does automatic redials for numbers that were busy or there was no pickup,” he said.

Phone numbers for residents with landlines are placed into the system’s database by the same company that provides the locations of people who make 911 calls, Nawrocki said. People who have only cellphones must go to a website to register their numbers.

System managers can determine what areas get the calls by mapping them on a computer screen or entering address parameters.

“But usually the simplest is to draw a radius around the incident,” Nawrocki said.

El Paso County has found that there can be delays if a larger area must be called, or if the system needs to call back many people who don’t answer, sheriff’s Lt. Lari Sevene said. Officials educate residents about what to expect on caller ID, so they don’t inadvertently ignore an alert.

Sevene said she also reminds residents near wildfires that they can leave before getting an evacuation call.

“If there’s a shift in wind, that shift could happen before we have an opportunity to change our messaging,” she said.

Copyright 2012 The Associated Press.