What's behind the snowmageddon that hit the US?

 作者:闵襄     |      日期:2019-03-05 10:04:02
IT’S been the warmest year on record globally. But tell that to residents of Buffalo, New York, who saw about 2 metres of snow last week as freezing temperatures hit much of the country. As New Scientist went to press, people were bracing themselves for possible floods from melting snow – and more snowfall was forecast for Thanksgiving. So what caused this unseasonal weather? Cold air is usually trapped in the Arctic by the winds that circle the pole. But kinks in the polar jet stream winds caused by ex-super typhoon Nuri, which moved north across the Pacific, allowed freezing polar air to spill as far south as Texas. This caused temperatures to plummet for several days. Winds blowing across Lake Erie picked up moisture and dumped huge amounts of snow in Buffalo, in a “lake effect”. Global warming is making the atmosphere more moist and may be weakening the jet stream, so strangely it may be contributing to more snowmaggedon events. This article appeared in print under the headline “Snowmageddon” More on these topics: