18 hours ago Lucy Sherriff Here’s how the polar vortex, and climate change, influence extremely cold winter weather in the US.
This blast of cold weather is due to activity of the polar vortex.
The polar vortex, or Arctic polar vortex, is a ring of strong westerly winds that form between 10 and 30 miles (16-48km) above the North Pole every winter, enclosing a large pool of extremely cold air.
The polar vortex doesn’t always influence the weather in the mid-latitudes, but when it does the effects can be extreme.
It is not known whether climate change will affect the polar vortex, says Amy Butler, an atmospheric scientist at the National Oceanic and Atmospheric Administration, and an expert on the polar vortex.
18 hours previously.
Mrs. Lucy Sheriff.
This is how climate change and the polar vortex affect the US’s bitterly cold winters.
The polar vortex has been causing severe snowy wintry weather in the United States, which has spread to engulf a significant portion of the nation.
A winter storm in early January forced seven states to declare states of emergency, halting flights, closing businesses, and dumping 625 feet (1.09 meters) of snow in a single day in one part of New York. Through mid-January, temperatures have remained below average due to another wave of Arctic air, and more wintry storms are predicted for areas of the Midwest, Appalachians, and Atlantic Seaboard.
The polar vortex is to blame for this burst of cold weather.
The polar vortex: what is it?
The polar vortex, also known as the Arctic polar vortex, is a ring of powerful westerly winds that encloses a sizable pool of extremely cold air every winter and forms between 10 and 30 miles (16–48 km) above the North Pole. The air inside is more isolated from warmer regions when the winds are stronger. In order to maintain the coldest air in the Arctic, the polar jet stream moves northward when the vortex is stable.
However, if this stable scenario fails, the US and other mid-latitudes may experience a severe cold snap. The winds in the vortex shift from a circular ring to a wavy band that loops farther south as it weakens. This releases the cold weather that is typically kept at the pole farther south.
Mid-latitude weather is not always affected by the polar vortex, but when it does, the consequences can be severe.
According to Brett Anderson, senior meteorologist at AccuWeather, “[the early January] cold outbreak and the one through the 16 January are basically broken off pieces of the polar vortex,” ABC reports. “It floats southward with the current, which is the jet stream winds, like a big piece of ice that breaks off from a glacier. “,”.
What impact does climate change have on the polar vortex?
Amy Butler, an atmospheric scientist at the National Oceanic and Atmospheric Administration and a polar vortex expert, says it is unclear if climate change will have an impact on the polar vortex. For a number of reasons, it is extremely difficult to forecast whether polar vortices will get stronger or weaker in the years to come.
According to Butler, “the polar vortex’s strength can be altered by a variety of factors.”. One of these is sea ice, which some models indicate may weaken the vortex as it melts. Warming in the upper atmosphere, however, may make the vortex stronger. Sea surface temperature variations by region may also have an impact on the vortex.
“For these reasons, there is no consensus among models regarding the future of the polar vortex in the Northern Hemisphere,” Butler explains.
How are US winter storms evolving?
Since the start of official records in the 1930s, the amount of snowfall in many parts of the United States has decreased. While the Great Lakes have historically received more snow, albeit only slightly, the Pacific Northwest and portions of the Midwest have experienced a decline.
One factor contributing to this overall decrease in snowfall is that more winter precipitation is falling as rain rather than snow, which is a result of warmer air temperatures brought on by climate change. In the contiguous 48 states, over 80% of weather stations have recorded a decline in the percentage of precipitation that falls as snow between 1949 and 2024. Furthermore, since 1972, there has been an average annual decrease of 2,083 sq mi (5,395 sq km) in snow cover, or the area of land covered by snow.
In general, North America has seen fewer and milder cold snaps. As a result of their rarity and less adapted societies, they can pose a greater threat when they do appear, whether in North America or elsewhere.
It may also be more difficult to prepare for cold snaps due to other changes brought on by climate change. Butler notes that “it’s possible that the type of precipitation could change, leading to some regions seeing more snow, and other regions seeing more ice or sleet events, which could have bigger impacts for, for example, transportation, than snow.”. This could put pressure on areas that rely on snowpack for water, though, as other areas might experience significantly less snowfall. 75 percent of the water supply in the western United States comes from snowmelt.
Climate change might also have unanticipated effects. Because a warmer atmosphere can hold more moisture that can fall as precipitation, Anderson says that when winter storms do occur, they can occasionally be more intense. The two fundamental requirements for snow are freezing temperatures and atmospheric moisture. Additionally, more moisture is now held in Earth’s warming atmosphere even though there are fewer freezes because winter is the season that warms the fastest in the majority of the US.
Anderson continues, “I believe that if warming continues, particularly in the oceans, there will be more energy and moisture available for bigger winter storms,” which can manifest as excessive snowfall or rain. In contrast to snow alone, we are witnessing a trend toward more rain or mixed events. “..”.
Anderson does acknowledge that he is unable to determine whether or not climate change is to blame for this specific cold outbreak. Nonetheless, he says that “short term variability” in the weather is something we can anticipate as a result of climate change.
According to Anderson, the big picture is obvious in the long run. While he acknowledges that many places will occasionally experience cold and snowy winters, he predicts that these cold outbreaks will become even less frequent over many decades or more. All of the long-term trends (30 years or more) that climate scientists study unequivocally demonstrate a warming trend that is largely caused by human activity. “.”
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