SEOUL (Reuters) - South Korea’s winter Olympics organizers have worries other than a ban on Russia competing, poor ticket sales and tensions over North Korea. They fear it may be too cold.

The Pyeongchang Games in February may feel like the coldest Olympics in at least three decades because the main stadium lacks a roof, leaving an estimated 35,000 spectators, including world leaders, exposed to extreme cold for the opening ceremony.

The organizing committee’s concerns are contained in an internal document, seen by Reuters, which expects biting winds to make conditions inside the open-air stadium at the start of the Games seem like minus 14 degrees Celsius.

That “feels-like” temperature is lower than the minus 11 degrees recorded at the 1994 Lillehammer Games in Norway, whose stadium also lacked a roof and is so far the coldest Olympics for which such data is available, the internal document shows. Reuters could not find comparable data for earlier Games.

South Korea, which built Pyeongchang’s $58 million stadium without a roof to save time and money, plans a range of measures at opening and closing ceremonies to prevent people suffering hypothermia -- from distributing hot packs and blankets to speeding up security checks, the internal document shows.

Organizers also plan to use audience participation during pre-ceremony entertainment to help keep spectators warm, the document says without giving details.

Graphic: Winter Olympics temperatures -

After the news last month that six people had reported hypothermia during a pop concert at the stadium, organizers are also considering installing more large windshields around the stadium, a sports ministry official said.

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“These are stopgap measures,” said Shim Ki-joon, a ruling-party lawmaker, who sits on a parliamentary special committee set up to support the Games.

“This is a very serious issue. This is creating a headache to not only the organizers but the presidential office, which sent officials to the venue to figure out ways to fight the cold,” he told Reuters.

A presidential spokesman declined to comment on the matter.

President Moon Jae-in has invited Chinese President Xi Jinping and Japanese Prime Minister Shinzo Abe to the Games, among other VIPs. U.S. President Donald Trump has committed to sending a “high-level” delegation, the White House has said.

Some 160 VIPs will be offered thicker and bigger blankets than those given to other spectators, a committee official said.

ORGANIZERS HAD REQUESTED A ROOF

The opening and closing ceremonies will both take place in the evening, on Feb. 9 and Feb. 25 respectively. Spectators will stay outdoors for four to five hours on each occasion.

In Lillehammer in 1994, the ceremonies were held outdoors and organizers scrapped the tradition of releasing doves, a symbol of peace, because they worried the birds might suffer. Instead, the Norwegians released white dove-shaped balloons.

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The International Olympics Committee discussed Pyeongchang’s cold weather at its executive board meeting this week, Olympic Games Executive Director Christophe Dubi told a news conference.

“It is not something we have not encountered in the past,” Dubi said on Wednesday, citing Lillehammer as well as the Salt Lake City Games in 2002.

“(Organizers) have installed windscreens and (provided) blankets and there will be plenty of information. In the last K-pop concert people were not well informed of how cold it could get.”

The cold weather is at least a manageable problem for the organizers. Its other headaches are less so.

Political tensions with North Korea and China have chilled foreign interest in the Pyeongchang Games, which open just 80 km (50 miles) from the world’s most heavily fortified border.

As of Dec. 5, ticket sales totaled 578,000, or 54 percent of target, though an organizer said that was similar to sales at a similar point ahead of the Sochi Games in Russia in 2014.

The International Olympic Committee has also banned Russia, which finished top of the medals table at Sochi, from Pyeongchang, citing evidence of state-sponsored, systematic cheating of doping controls.

Pyeongchang organizers had urged South Korea to equip the stadium with a roof and heating, but this was rejected due to costs and concerns over whether the structure would support a roof. The temporary arena is to be dismantled after the Games.

The culture and finance ministries, both involved in approving construction costs, did not respond to requests for comment.

“The cold could ruin the entire opening party. The fate of the event is down to the mother nature,” said ruling party lawmaker Yeom Dong-yeol at the Pyeongchang parliamentary committee, who was born and raised in the town.