Similar events took place in Europe in 20. At the same time, by sweeping in moist air from the Atlantic, it caused extreme precipitation and flooding across many areas in central and eastern Europe. The January-February 2019 event brought extreme low temperatures to both southern France and Sweden. The same pattern often hits on the other side of the Atlantic at the same time, usually most most extreme in southwestern Europe and Scandinavia. Synchronized Weather Events in North America and Europe A similar though less destructive event caused a January-February 2019 cold snap in the eastern United States, killing more than 20 people. All told, at least 278 people were killed directly or indirectly by the cold wave, and there was nearly $200 billion in damage.

Hardest hit: Texas, where record cold paralyzed natural gas pipelines and other energy infrastructure, knocking out much of the electricity grid and causing homes and businesses to go dark and freeze. Parts of the Deep South saw rare snowfall. Temperatures fell as much as 50 degrees F below average as far south as the U.S. The most recent major wave-4 iteration brought a February 2021 cold wave to much of Canada, the United States, and even northern Mexico.

At the same time, abnormally warm or dry conditions may develop in the peaks. The authors say that when this happens, the chances of extreme cold or wet in the trough triples. A winter pattern known as a wave-4-globally, four peaks and four matching troughs - tend to lock in place. The newer paper shows more or less the other side of the coin. These can cause widespread, simultaneous crop losses in important breadbasket regions, the study said. In a 2019 study, Kornhuber and colleagues showed that a repeating Rossby wave pattern known as a wave-7-that is, seven giant peaks and seven matching troughs spanning the globe-draws warm, dry air from the subtropics up to the midlatitudes, causing concurrent summer heat waves and droughts in predictable parts of North America, Europe and Asia. Given the right conditions, certain of these wobbles can become amplified into symmetrical waves that then lock in place across the globe, somewhat similar to the vibrations that produce a constant musical pitch. Some scientists think these wobbles are increasing in size and frequency due to rapid warming in the Arctic that is far out proportion to more southerly regions this destabilizes the system, generating winds that break down the north-south barrier, they say. It generally flows within relatively straight boundaries, segregating cold polar air masses from the midlatitudes, but at times it can naturally develop big wobbles. The jet stream is a fast-moving river of air that continuously circles the Northern Hemisphere from east to west. But today and going forward, cold is still a very relevant hazard.” “A hundred years from now, we will probably not have to worry as much about extreme cold, because everything is getting warmer. “Even though winters are getting milder on average, it’s happening at the expense of increasingly devastating heat extremes in the warm season,” said author Kai Kornhuber, an adjunct scientist at Columbia University’s Lamont-Doherty Earth Observatory. Understanding Jet Streams and Weather Anomalies The new paper was published this week in the Bulletin of the American Meteorological Society.

In just the last few years, they have killed hundreds of people and paralyzed energy and transport systems. Such weather waves, they say, have doubled in frequency since the 1960s. The study’s authors say they have identified giant meanders in the global jet stream that bring polar air southward, locking in frigid or wet conditions concurrently over much of North America and Europe, often for weeks at a time.

Saw spiral stream