The body of an unidentified man was found in a Georgetown alley yesterday morning, one of three apparent victims of hypothermia caused by the weekend's unusually frigid temperatures.

The District's medical examiner's office said the man probably died of exposure and that tests will be conducted today to determine the exact cause of death.

D.C. police Detective Willie Jefferson said the man was discovered around 7 a.m. near a heat grate at Canal Square. A maintenance worker reporting to work found the body, Jefferson said.

Next to the man's body was a bulky gym bag that contained several changes of clothes and other personal items, police said. The man, believed to be in his forties, had on several layers of clothing, Jefferson said. Police said there were no signs of violence.

Police said they found a second hypothermia victim, identified only as a man in his 40s, in the 300 block of 12th Street NW about 7:30 Sunday morning. And a third unidentified man apparently froze to death late Saturday night shortly after he was brought to Howard University Hospital by a private ambulance, police said. They said they did not know where that man was found.

The three cases would raise the total number of hypothermia deaths this winter to five.

The deaths rekindled concern about the plight of the homeless when the thermometer plunges to below freezing temperatures.

"We try not to turn anyone away," said Ricardo Taylor at the Bethesda Men's Shelter in Bethesda, where fire marshals recently placed a 30-person limit on the facility after it had housed as many as 50 people on several cold nights in November.

"If you turn someone away," Taylor said, "it could be their last {chance to} sit" before freezing to death.

The low yesterday at National Airport was 11 degrees, according to Scott Prosise with the National Weather Service. Today's forecast calls for highs near 40 under partly sunny skies, but an arctic blast is expected to return to the area tomorrow, when temperatures will drop to 30 degrees with a 30 percent chance of light snow, Prosise said.

On average, temperatures for early February are a high of 44 and a low of 28, he said.

Despite the cold, many homeless people refuse to seek shelter inside a warm building, preferring to sleep on heating grates or in abandoned buildings, shelter operators said.

During the past five winters, 54 people, including 30 homeless people, have died from hypothermia in the District, according to a spokesman for the medical examiner's office.

The city's first fatality attributed to this winter's cold was John Wilks, a homeless man found dead Dec. 31 in an abandoned car. About a week later, a unidentified homeless man believed to be about 50 years old was found dead in the 1200 block of G Street NW in a parking lot attendant's booth, according to the medical examiner's office.

Last weekend, most of the government-run and private shelters in the area had enough beds for the homeless who knocked at their doors, officials said.

The D.C. Council passed emergency legislation last month authorizing the city to use certain public buildings as shelters when temperatures fall to 25 degrees or below.

But Earnest Taylor, director of emergency shelters and support services, said he has not had to open the ground floor of the District Building or the Randall School building in recent weeks.

"I have not had to bring them on line because we've had enough space in our other shelters," Taylor said. "At this point, I'm safe," he said.

Since Friday, the city's hypothermia unit has picked up about 40 homeless people each night and transported them to shelters, Taylor said. He said the number was about average for the winter cold snap.

City officials said temporary overnight shelters have taken some of the burden off privately run facilities, such as the Community for Creative Non-Violence shelter at Second and D streets NW, where a spokesman said about 650 people were housed yesterday.

Taylor said the city has erected two trailers that can sleep 18 homeless men each at Mount Vernon Square, while a retrofitted Metrobus at 17th and I streets NW can accommodate 30 homeless men.

But shelters can do only so much, he said, noting that some homeless people refuse free rides to shelters.

"They will not leave no matter what," Taylor said. "A lot of these guys can articulate well enough to know what's going on. But to them, freedom is the last vestige that they have to hold on to."