UPDATE: Officials with the Alaska Division of Forestry are planning to hold a media briefing at 9:00 p.m. on the status of the McHugh Fire. KTUU.com will livestream the briefing.

3:20 p.m. TUESDAY UPDATE:

AFD strike team moves to Potter Marsh

An Anchorage Fire Department assistant chief said AFD firefighters have done all they can to protect the 17-home Rainbow subdivision and are turning their attention to prevention efforts at nearby Potter Marsh.

The Rainbow neighborhood has not been evacuated and the fire has not reached it. Assistant chief Alex Boyd said the fate of the homes is now out of their hands as the AFD "strike team" focuses on creating a fire break at Potter, on the outskirts of Anchorage, in case winds change and accelerate flames toward the city.

Officials had no new size estimate for the wildfire, which was 500 to 600 acres as of earlier today. The cause of the fire is under investigation.

2:30 p.m. TUESDAY UPDATE: Road closure possible, city issues smoke advisory

Latest developments on the McHugh Fire, based on interviews with Forestry and Anchorage Fire Department officials:

- The fire is moving at about 50 feet per hour toward Potter Marsh, said AFD assistant chief Alex Boyd. For fire crews, the priority remains protecting Rainbow subdivision and Indian. People in those areas should gather belongings in case they are told to evacuate.

- Drivers are urged to stay away from the Seward Highway south of Anchorage. Lane closures have been expanded to Potter Marsh with traffic backed up for a two-hour wait or longer. Anchorage police warns the highway might be closed "at any point" as the wildfire grows.

- The size of the fire was estimated mid-day at 500 to 600 acres based on flight observations. That’s larger than Merrill Field, or nearly one square mile.

- Flames are within 1.1 miles of Rainbow subdivision, which has about 17 homes. The small community sits along a dirt road that winds uphill surrounded by Chugach State Park. It is next to the Rainbow trailhead at mile 108 of the Seward Highway.

- Flames are about 1.3 miles from Potter Marsh. The main head of the fire is growing to the south, but the fire is also “backing up” toward Potter Marsh despite winds in the opposite direction.

-

is in place today for Anchorage.

- As a precaution, Division of Forestry spokesman Lori Wiertsema said South Anchorage residents should consider gathering belongings in the unlikely event the fire draws closer.

- Smoke from the fire has

from the city for Turnagain Arm and some South Anchorage locations.

- Due to the fire response, state officials have closed Chugach State Park trails and nearby park lands to public use between the Potter Creek and the Rainbow trailheads, according to the Department of Natural Resources.

The closures include Turnagain Arm trail between Potter and Rainbow, the McHugh Creek trail, and the Rainbow Peak trail. Also closed are the McHugh Creek wayside, Beluga Point pullout and Rainbow trailhead.

12:45 P.M. TUESDAY UPDATE: 'Everyone is holding their breath'

In Rainbow, meanwhile, residents are sitting tight waiting to see if firefighters order them to evacuate.

“Everyone is holding their breath,” said Bob Childers, president of the Rainbow Valley Homeowners Association.

Fire crews came through the community at around 1:30 a.m., Childers said. They were checking maps to make sure they knew where each residence is located, and they were also locating water sources.

“They were trying to get a lay of the land,” he said.

Ken McCormick, a Rainbow resident, was fishing on the Kenai on Tuesday. Reached on his cell phone, McCormick said he is staying in close touch with Childers about whether an evacuation will be needed.

“I’ve heard it’s up in the air but that it would be good to grab your valuables and stand by,” McCormick said.

Childers said the incident commander is in touch with him and will notify residents if and when it’s time to go.

“People are being remarkably calm. Many have put together a carload of stuff,” Childers said. “We’re just kind of hanging out.”

NOON TUESDAY UPDATE:

As crews work to protect the Rainbow subdivision, the McHugh fire has ballooned to 500 to 600 acres with more firefighting crews on the way, the Division of Forestry says.

Two air tankers, multiple helicopters and more than 50 firefighters are battling the blaze, said Division of Forestry spokeswoman Sarah Saarloos. Additional “hotshot” crews are expected and two Blackhawk helicopters will likely be staged out of Girdwood with a firefighting command center in South Anchorage.

Crews are working to protect homes in the nearby 17-home Rainbow subdivision, Forestry and Anchorage Fire Department officials are telling KTUU. The flames have advanced about a mile northwest toward Anchorage while the main head of the fire still moving south, according to interviews with Forestry spokeswoman spokesman Lori Wiertsema and Boyd.

Officials said the flames are about 1.1 miles from Potter Marsh and 1.3 miles from the Rainbow subdivision.

The fire is fueled by long-dead trees, Saarloos said.

“That’s just adding to the amount of heat and smoke that everyone is seeing,” Saarloos said. “When the trees burn, they burn through the roots and then they roll down. As they are rolling down, they pick up rocks and ground and that’s what we’re starting to see roll into the Seward Highway.”

The Department of Transportation has warned of a possible road closure as the wildfire snarls traffic on the Seward Highway.

“It has kind of burned into that high cliff face and down to the highway at certain points there between Mile 108 and Mile 113,” said the Division of Forestry’s Phil Blydenburgh. The newly estimated size – which Blydenburgh said is based on flight observations in the area -- of the fire is now larger than Merrill Field.

Saarloos said drivers, unused to seeing fires burning on the roadside, must remain with the flow of traffic rather than stopping or slowing to watch the flames and firefighting efforts.

“What we really need is the assistance of the public right now to follow the traffic pattern. Do not stop. Watch the signage,” she said.

TUESDAY MORNING UPDATE:

The McHugh fire south of Anchorage has grown to more than 100 acres as of Tuesday morning, said Division of Forestry spokesman Lori Wiertsema.

Traffic on the Seward Highway was limited to one lane this morning from Mile 108 to Mile 113 due to firefighting efforts, according to Anchorage police. Drivers should expect delays.

The blaze was estimated at 60 acres as of late Monday, when it was within 1.7 miles of the Rainbow subdivision, according to an Alaska Inter-Agency Coordination Center report. It had grown to 100 acres as of 7:45 a.m. this morning, Wiertsema said.

"Fire made a push up the drainage making short runs with intermittent torching, making several spots over the retardant line over 1/2 a mile away," the report says. "Crews worked bucket ships to assist holding their line."

Meantime, the National Weather Service has

for Turnagain Arm and the Anchorage area until 10 p.m. tonight.

That means that with temperatures in the mid 60s to lower 70s at higher elevations, and the upper 70s in valleys, growth and spread of wildfires is possible, according to the Anchorage Office of Emergency Management.

Police announced the lane closure at 6:03 a.m. At that time, southbound lanes were open with a pilot car leading drivers through the area.

Division of Forestry spokeswoman Lori Wiertsema said officials are trying to close scenic pullout stops to traffic in conjunction with the lane closure.