As this winter plods along, here's a fact to chill the blood: An average of 689 American freeze to death each year. 

Medical experts complain that hypothermia is almost always preventable. But dozens of people have frozen to death in recent days as the sudden February cold snap threatens hundreds of homeless and elderly people living on the streets or in inadequately heated structures. 

Most prone to freezing are people living in Alaska, New Mexico, North Dakota and Montana. But even Virginia, North Carolina and South Carolina have posted significant death rates by the cold. 

Seventy percent of the Americans who died of hypothermia in 2003 were men with a median age of 61, according to federal death records recently released by the National Center for Health Statistics. 

"That's pretty much the kind of people we are getting here," said Laura Derby, administrator of Rising Hope United Methodist Church in Alexandria, Va., which began a hypothermia center for homeless people three weeks ago. "People will come forward to help a woman, especially if she has kids, to check into a hotel when it gets really cold. But they rarely help a single man." 

Not all victims of the cold are vagrants, however. At least 142 people died in their homes in 2003, often poor and elderly residents with inadequate heating. 
About 82 percent of the victims were single, divorced or widowed. A disproportionate number were black or of other racial or ethnic minorities. 
Emergency workers and charitable organizations, lulled by an unusually warm January in much of the nation, scrambled to establish emergency shelters this month in hopes of reducing the hypothermia death toll. 

"We just barely opened in time," said Derby. "Three people froze to death in our county last year. We don't want that to happen again. Right now, we are taking in on a regular basis about 20 men and women each night, and that's the maximum we're allowed to have." 

The Baltimore City Health Department recently upgraded its "Code Blue" program to monitor 911 calls so that health workers can respond quickly to any weather-related injuries. Authorities are educating the staffs of 18 overnight emergency shelters on the symptoms of hypothermia, which include involuntary shivering, slowed or slurred speech, confusion or sleepiness and poor control of body movements. 

"It's a tragedy every time someone dies for lack of a regular place to stay," said Baltimore Health Commissioner Joshua Sharfstein. "We will take additional steps to prevent unnecessary deaths." 

January historically is the deadliest month, with February not far behind. In 2003, 168 people died of hypothermia in January, 135 died in February and 123 died in December. But cold-related fatalities also occurred in the summer, often among swimmers or people exposed to cold water. Six people died of hypothermia that July. 

Forty-eight people died of cold weather in Pennsylvania three years ago, the most of any state. Another 45 perished in New York, 36 died each in Michigan and California, 23 in Arizona and 22 each in New Jersey and Virginia. 
Among recent hypothermia fatalities: 

- Pauline Gossage, 85, of Mount Vernon, Ill., found dead in subfreezing weather after suffering a seizure outside her home. 
- An unknown Mexican man in his late 40s whose body was found Monday at an illegal border crossing south of Tucson, Ariz. 
- Paul Crumpton, 58, a homeless man whose body was found on a grassy area near an off-ramp to Interstate 5 in Vancouver, Wash. 
- Michael Bitner, 51, of La Center, Wash., also homeless, found inside a compartment of a truck trailer where he apparently went to sleep.