US authorities have warned of the risk of hypothermia and frostbite, inviting residents to stay inside their homes in the face of the approaching winter storm.
As Christmas approaches, the United States is facing a winter storm of unprecedented magnitude, “occurring only once in a generation”, estimated the National weather service, the American meteorological service. President Joe Biden called on his fellow citizens to take the alerts “very seriously”.
The mercury is expected to drop lowest in the Great Lakes and the Midwest, with up to -55°C felt in the Great Plains region. In Denver, -20°C were measured this Friday, -21°C in Chicago.
The dangers of hypothermia
With such temperatures, what do the inhabitants of these areas actually risk if they venture outside or if their accommodation is not or poorly heated? On his websitethe main American health protection agency, the Centers for Disease Control and Prevention, recalled the dangers that the cold poses to health.
Hypothermia is the most dangerous consequence, “caused by prolonged exposure to very cold temperatures”.
In hypothermia, which occurs when body temperature drops below 35°C, the human body loses heat faster than it produces. If the victim is not taken care of or warmed up, he can die of cold, by cardiac arrest.
“During severe hypothermia, the heart will beat much less quickly”, underlines for BFMTV.com the general practitioner Jérôme Marty, who recalls that a person can always be resuscitated if his body temperature returns to a normal threshold.
Frostbite and amputation of limbs
The cold can also paralyze the brain, making it impossible for the person to move or speak. “A feeling of well-being can even be felt shortly before falling into a coma”, adds Jérôme Marty.
Frostbite is the second threat posed by these polar temperatures. These are wounds affecting the extremities – fingers, toes… – and which occur following the contraction of blood vessels. The tissues are no longer oxygenated, and the water in the cells freezes. In the most serious cases, amputation is necessary.
After the announcement of the forecast for the Christmas weekend in the United States, the National weather service indicated: “Cold weather of this magnitude could cause frostbite on exposed skin within minutes, as well as hypothermia and death if exposure is prolonged.
Die of cold by 4°C
However, temperatures as extreme as -55°C need not be reached for the cold to pose a threat. The American authorities mention a risk from 4°C.
“You can die of hypothermia by -10°C, even when the temperature is a little positive. It’s actually a problem of heat exchange, says Jérôme Marty to BFMTV.com.
“If a person is wet or submerged in cold water, temperatures don’t have to be frigid to be fatal. However, the colder the temperature, the faster hypothermia will set in. “, he adds.
Infants and the elderly are most at risk. The former because they lose temperature faster when exposed to cold, the latter because they produce less body temperature than an adult.
A three-level ladder
In countries accustomed to extreme cold, such as Canada, or for high mountain climbers, a temperature scale has been set up to remind you of the best practices to adopt.
On the Quebec government website, three levels of severity are distinguished, depending on the temperature felt. Between -10°C to -47°C, there is a “low to moderate risk” of hypothermia, “if left outdoors for long periods without adequate protection”.
From -48°C to -54°C, there is a serious risk “if left outdoors for long periods without adequate protection”. Finally, below -55°C, the risk is high, it is recommended that residents do not leave their homes.
Properly covered, humans can therefore survive outside during severe polar cold spells. The ideal is to wear several layers of clothing. The air between each layer is an excellent insulator.
