(Editor's note: This story includes a correction.)

Howling winds and snow grounded an effort Thursday to find a small plane missing in a mountainous area of Antarctica for more than two days, rescuers said.

The twin-engine plane, carrying three Canadian crew members, was about an hour into a flight from the U.S.-run Amundsen-Scott South Pole Station to an Italian research station at Terra Nova Bay, when its emergency beacon was heard by rescue officials in Wellington, New Zealand, at about 10 p.m. local time Wednesday (4 a.m. ET)

The company that owns the plane, Kenn Borek Air Ltd. of Calgary, Alberta, said it was "maintaining a respectful silence" until the fate of the plane and its crew was known.

The Calgary Sun newspaper identified one of those aboard the plane as Bob Heath of the Northwest Territories, calling him a "star pilot" for Kenn Borek Air.

www.nsf.gov

A file photo shows a twin-engine Otter, the type of plane missing in Antarctica with three Canadians aboard.

The newspaper quoted Heath’s wife Lucy Heath as saying she was “worried” and “waiting for news.”

A search plane spent about five hours circling over the site of the beacon, which is in a mountainous area, but heavy cloud cover hampered the search and then the weather got worse, officials said.

Winds have topped 100 mph and it was also snowing, Michael Flyger, spokesman for New Zealand’s Rescue Coordination Center, said.

He added he hoped the next weather forecast "will bring good news,” enabling the search to continue.

Five-day water supply
The beacon’s signal is coming from an area about 11,000 feet above sea level, Flyger said.

"It’s pretty mountainous terrain. It’s impossible to say whether it crashed or made an emergency landing or they had a mechanical problem and had to ditch the plane," he said. "At the moment we have a plane that’s not where it should be and a locator beacon is going off."

The beacon can be switched on manually, but it also would begin transmitting if sensors detected a crash, Flyger said.

Despite the conditions in the area, there may be reason for optimism, he added.

"We do know that onboard the aircraft there was a significant amount of survival equipment — heavy-duty mountain tents, enough water for three people for five days,” he said. “They’ve certainly got the equipment to look after themselves."

The National Science Foundation, which manages the U.S. Antarctic Program, said the plane was flying in support of Italian Antarctic research.

Searchers from the United States, Italy and Canada are assisting in New Zealand's efforts and have helicopters and airplanes ready to return to the site, Flyger said, adding that the the ideal scenario would be for a helicopter to either land or use a winch to bring up survivors.

"If conditions are good enough, hopefully we can land a short distance away and the team will walk to the crash site," he said.  "There’s some frustration that the weather has been the way it’s been. The searchers are very keen to get in and crack on with the job."

"We’re very aware that not only are there people out there who need our help, but there are people ... wanting to know what’s going on. We hope to be able to give some good news."

Related:

Plane with 3 on board missing near South Pole

(Editor's note: This story includes a correction.)

An aircraft carrying three men went missing in Antarctica on Wednesday and the plane’s emergency locator beacon was activated, according to the National Science Foundation.  

The status of those aboard remains unknown, NSF spokesman Peter West said. The Toronto Star reported that the three men are Canadian.

West said those aboard were likely a pilot, co-pilot and a flight engineer carrying or picking up cargo. They had been contracted to support a branch of the Italian Antarctic Program that focuses on new technology and energy – specifically nuclear fusion and fission.

The aircraft, a de Havilland Twin Otter, was returning from the South Pole to Terra Nova Bay, where the Italian Antarctic Program is based, when contact was lost as the plane flew over a remote area of the Transantarctic Mountains.

The plane was contracted out by Kenn Borek Air Ltd., a Canadian company based in Calgary that charters aircraft to the U.S. Antarctic program.

Rescue crews, based at the New Zealand Rescue Coordination Center, know generally where the beacon is coming from, but cloudy and windy conditions have prevented rescue planes from attempting a landing near the downed plane.

“There are not as many weather stations, so it’s difficult to find out what the weather is,” West said. “There was low cloud, limited visibility in the air in the area where they were looking for the aircraft -- some blowing snow and issues with cloud.”

www.nsf.gov

A Twin Otter aircraft, photographed here in 2006, at the National Science Foundation's Amundsen-Scott South Pole Station.

West said he didn’t know whether the flight crew carried cold weather survival gear. At the U.S. station, protocol demands that anyone leaving the base must have protective gear – typically a parka, wind pants, insulated boots, a tent, food and a stove to melt snow into water.

He said that he doesn't recall a similar crash in his 14 years as a spokesman for the Antarctic program.

Antarctica, the size of U.S. and Mexico combined, is vast, white and isolated. There are about 50 research stations, some of them year-round, others open during research season, which runs roughly between October and early February – summer in the Southern Hemisphere. During those months, the largest is McMurdo Station, the U.S. Antarctic station on Ross Island, with about 1,100 people.

“It’s a harsh continent,” West said. “People take extra care if they can.”

AP, file

British adventurer Felicity Aston skis across Iceland during a pre-expedition training trip in Sept. 2010.

High winds and poor visibility have slowed a British explorer's bid to become the first woman to cross Antarctica alone, but improving conditions are boosting the 33-year-old's hopes of reaching her destination within two weeks.

"I was really pleased to wake up this morning and find that that the weather has drastically improved," Felicity Aston said in a podcast posted at on Tuesday night. "The winds have dropped a bit and I could actually see something so there was some visibility.  I could see the horizon and there was some surface contrast as well so I set off pretty quick. It's been a great day."

If successful, Aston would become the first person using only muscle power to cross Antarctica alone, according to The Associated Press. Boerge Ousland of Norway previously made a 64-day trip across the continent in 1997, but he harnessed the wind when it blew in his favor by strapping himself to a parachute-like sail.

Aston told the AP on Tuesday by satellite phone that she had skied about 140 miles so far.  In her podcast, she said she was within 200 nautical miles of the pole, which was "nice but we do need to be closer."

"All in all I'm about five days behind, but all these things are relative, so it's not disaster yet," she told the AP.

Aston had hoped to make it to the South Pole by Dec. 13, the centennial of Norwegian Roald Amundsen's achievement in leading the first team to reach the pole. More than 30 teams are currently heading for the South Pole, trying to make it in time for an anniversary celebration.

"I'm going to miss the party," Aston told the AP. "It's still lovely in the 100th anniversary year to be out here."

• Pictures: U-haul to the North Pole

Aston sounded upbeat despite running behind schedule.

"I hope (favorable conditions) actually continue for a while longer because I did really well today, I did 14.6 nautical miles, which I think is my biggest day yet," she said. "I'd like a few more of those to get me closer to the pole."

According to Aston's website, the explorer first went to the Antarctica at age of 23 and spent three years living and working as a meteorologist with the British Antarctic Survey.

When she returned to Britain, she was part of the first all-female team to complete a 360-mile endurance race across the Canadian Arctic.  A year later, she led the first British women's crossing of the Greenland ice-sheet.

Since then she has led a number expeditions including the Kaspersky Lab Commonwealth Antarctic Expedition, the largest and most international women's expedition ever to ski to the South Pole.

The Associated Press and msnbc.com staff contributed to this report.

• We are the median: Military makes $50,000 feel like more
• NBC: Downed drone spied on Iran nuke facilities
• Activists ask: Undercover cop? Or one of us?
• A consumer's tale of a credit report 'Catch 22'
• Sandusky's dinner with alleged victims raises questions
• We are the median: Living on $50,000 a year
• Kids pay biggest price for world's gold craving