More than a thousand canceled flights and 44 states on alert. Blizzard, snow, gusts of wind and rain… It’s an explosive cocktail that has been hitting the United States since Wednesday. Add to that millions of Americans planning to travel for the holiday season, and the country’s authorities are on alert.
This storm will strengthen through Friday and continue through Christmas weekend. The AccuWeather meteorological site, as well as many media, warn about the possible formation of a “cyclone bomb”. According to CNN, this is expected to happen Thursday night and Friday.
It is, by its magnitude, “a storm that occurs only once in a generation,” the National Weather Service (NWS) warned on Twitter.
Overlapping of warm and cold air masses
The term “bomb cyclone” may sound spectacular. However, they are not that rare since, according to a study, there are about 18 per year on the continent. It is, on the other hand, the magnitude and intensity of the current phenomenon, together with its moment, which attracts attention.
Specifically, it can be classified as such a storm when the central pressure of the low pressure system drops at least 24 millibars (term used to measure atmospheric pressure) in 24 hours.
In other words, it means the storm is rapidly intensifying, with more devastating consequences than a single storm.
“It occurs when a cold air mass collides with a warm air mass, such as air over warm ocean waters,” says the US Oceanic and Atmospheric Observation Agency.
In this case, it was particularly cold air from the Arctic that moved south, passing over the warmer waters of the Atlantic Ocean. The overlapping of warm and cold air masses causes a drop in atmospheric pressure and instability, which triggers the process of “cyclonic bombardment”.
“Pressure of a Category 3 Hurricane”
Therefore, these intense storms usually occur during the winter. Winds pick up significantly and precipitation, including snowfall, can become heavy.
Blizzard conditions, characterized by poor visibility in snow, wind, and snow, can also occur, which is of particular concern for travel by car or plane. Heavy rains can also cause coastal flooding.
“The storm is expected to reach the equivalent of Category 3 hurricane pressure when it reaches the Great Lakes,” CNN writes Tuesday.
The gusts can reach 95 km/h, causing possible tree falls and power outages. Locally, more than 30 cm of snow could fall.
-43°C in one hour
Another characteristic of this “cyclone bomb”: extreme cold. The mercury drops very sharply in a few hours and could reach temperatures as low as -55°C in the Great Plains region, according to forecasts.
“Cold weather of this magnitude could cause frostbite on exposed skin within minutes, as well as hypothermia and death if exposure is prolonged,” the National Weather Service warns.
According to CNN, “More than 60 million Americans, or nearly 20% of the US population, will experience freezing temperatures with this arctic blast.” And this cold wave has already begun: in the city of Cheyennein Wyoming, the mercury dropped 30 degrees in ten minutes, then 43 degrees in an hour, CNN reports.
Meteorologists particularly highlight the difference between the measured cold and the perceived temperature, which can be even much smaller due to intense winds and precipitation. While some regions will be able to escape the heavy snowfall, all will be affected by this extreme cold.
Source: BFM TV
