The fear that a significant storm would blow up the 5,936-acre Cascade fire Tuesday diminished somewhat in the evening as predicted storm fronts shifted north.

"We thought the wind was going to be worse than it was," said Dixie Dies, fire information officer. "We're still on a red flag warning through the night."

A red flag warning issued for south-central Montana Tuesday portended high winds, lightning and little rain. By 10 p.m., that storm hadn't materialized west of Red Lodge in the West Fork Rock Creek drainage where the Cascade fire was burning.

"The rest of the storm tracked well north enough of the fire that it wasn't a problem for us," said Patrick Gilchrist of the National Oceanic Atmospheric Administration at the fire command's headquarters at the Carbon County Fairgrounds.

But Gilchrist was forecasting warmer air overnight, meaning less humidity and better conditions for the fire to continue burning hot. Combined with more warm weather today, the forecast means heightened fire conditions with 30 mph ridgetop winds and breezes blowing 20 to 25 mph in the West Fork drainage. Another storm front could also move into the area this evening with the potential for high winds and dry lightning.

Red Lodge Fire Chief Tom Kuntz told residents at a morning meeting to be ready to evacuate in the event that the blaze burns out of the narrow West Fork canyon toward Red Lodge.

"The fire is going to be completely weather-driven," he said.

Kuntz said there would "very likely be crown fire with rapid rates of spreading and long-range spreading," meaning the dry pine trees lining the canyon are likely to ignite and send embers up to half a mile away.

The narrow canyon has caused the fire to "reflect off itself," Kuntz said. Fires on both sides of the canyon are feeding off each other.

The fire had burned more than 5,930 acres and was about two miles from the Red Lodge Mountain Resort and nine miles from Red Lodge. Employees at the resort continued running snow-making guns to wet down lodges and lift shacks.

Crews focused on creating a fire line on the west end out of the West Fork drainage up onto the north ridge flanking the fire.

A new line of evacuation was set at the corner of Ski Run Road and Highway 212, affecting structures west of that line. The Forest Service and the fire crews would determine when the evacuation would become mandatory, while officials told house owners to start packing.

"Being prepared is absolutely essential," Kuntz said. "It is likely you will be evacuated."

Fire officials were confident they could save the city if the fire made it out that far, but an evacuation plan was laid out for those in town.

In the event of an evacuation of Red Lodge, an alarm will sound continuously throughout the city, phone calls will be made and sheriff's deputies will go door to door.

The only mandatory evacuation in effect is of the Grizzly Peaks subdivision, where there are about 90 homes.

Near the mouth of the canyon, Mike and Margot Narum kept their eye on the column of smoke rising from the mountains as they prepared to flee if necessary.

Their truck packed, Margot Narum scanned the Internet for fire updates while Mike photographed each room of their house for insurance purposes in case it burned.

"It will take us two seconds to get out of here," Margot Narum said. "We're ready."

Greg Mohl, a geologist and resident of Tipi Village on Ski Run Road, said he was watering his roof as a last line of defense against flying, live embers that could come from the canyon.

"If it makes the front, it's going to throw fire brands this far at least," Mohl said. "We're just hoping we're defendable."

Mohl and his son thinned out the tree limbs around their two-story house and left a note for fire crews telling them to cut down whatever they needed to.

He said they began preparing their house for a wildfire on Sunday. The practice from the Willie fire of 2000 helped his family gather up the essentials.

"I hate to think we're becoming old hat at this," Mohl said. "Suddenly painting the deck doesn't seem so important."

Mohl also said he had been on a hike up West Fork after the windstorm in November created a blowdown.

"If you were a Boy Scout and were told how to build a bonfire, that's how the wood is laid in there," he said.

Wally Bennett, incident commander for the Type 1 response team, said the fire crews were trying to establish an anchor point from which to work. Fire crews have camped on the northern and southern ridges overlooking the canyon and have thinned out the southern side near Senia Creek.

"We're going to be aggressive when we have the opportunity, but we're not going to put anyone in harm's way," Bennett said.

The fire crews' main objective is firefighter safety, to protect the community and defend the ski area, Bennett said.

The American Red Cross has set up a shelter for evacuees at the Joliet Community Center. Earlier reports that Red Lodge evacuees would go to MetraPark in Billings are incorrect.

A voluntary medical evacuation was recommended for Red Lodge Tuesday after the state Department of Environmental Quality downgraded the air quality from "unhealthy" to "very unhealthy."

The recommendation was issued to the people in the Red Lodge area with chronic heart or lung disease, including those with chronic obstructive pulmonary disease, emphysema, asthma, coronary artery disease and congestive heart failure. They are advised to vacate the Red Lodge area as soon as possible.

Children and the elderly have been advised to stay indoors and avoid physical exertion.

Beartooth Hospital and Health Center spokeswoman Melissa Scianna said staff members were compiling lists of patients and people in the area who may be affected by poor air quality caused by smoke.

Scianna didn't know how many people the order affects in Red Lodge. Of particular concern are the 17 intermediate-care patients - residential patients with care needs similar to those in long-term care - at the hospital. Those patients have been given the option to leave voluntarily, Scianna said.

"If they want to (leave), they can," she said.

Buses have been prepared for those patients, who may be transferred to a health care provider in Billings.

The hospital also was working with Billings Clinic on an emergency plan to transport patients from Red Lodge to Billings if the town were evacuated. Billings Clinic spokesman Luke Kobold said the hospital is prepared to take in all of Beartooth Hospital's patients in the event of an evacuation.

"We're prepared to act quickly," he said, although the exact number of patients was not readily available. "We have shared what their census is, and what they have we can accommodate."

However, officials from both centers hope an evacuation is not necessary.

Beartooth Hospital spokeswoman Melissa Scianna said the medical center will stay open as long as possible without compromising patients' health conditions.

Two informational phone lines are up and running. To reach the phone bank at the incident command center call 446-4893 or 446-4894.

Volunteers are needed to help people move pets and livestock and for other fire-related tasks.

Volunteers should have effective transportation, make sure their own property is taken care of, must have a cell phone, flexible schedule and be in good health. To find out more about volunteering, Call Beth Hutchinson at 446-1718.

Evacuees also can register on the American Red Cross' Safe and Well Web site, via www.redcross.org. People can post messages for family and friends to let them know they are safe, and concerned family and friends can search for evacuees.

The Festival of Nations scheduled for this weekend in Red Lodge was canceled. The Civic Center is being used for the Red Cross and for various staging efforts and officials are encouraging people to stay indoors because of the poor air quality, precluding outside events at Lions Park.

Cascade fire

Size: 5,936 acres (9.275 square miles).

Location: Nine miles west of Red Lodge.

Date started: July 26.

Containment: Zero percent.

Evacuations: At least 90 homes in the Grizzly Peak subdivision, voluntary evacuation for lower West Fork of Rock Creek.

Cause: Undetermined

Personnel: 496 people, including seven Type I and seven Type II twenty-person hand crews and 109 overhead support staff.

Agencies: U.S. Forest Service, Red Lodge/Carbon County Rural No. 7, Stillwater and Yellowstone Counties Rural Fire Departments, Montana Department of Natural Resources and Conservation, Bureau of Land Management, Bureau of Indian Affairs, United States Fish and Wildlife Service, National Park Service.

Equipment: 21 engines, two water tenders, two bulldozers, five helicopters, heavy airtankers.

Billings Gazette reporters Molly Priddy, Brett French and Zach Benoit and Associated Press reporter Matthew Brown contributed to this story.