Tempesta di neve in Usa e Canada: freddo polare e oltre 4mila voli cancellati

Picchi e record di freddo (in Wyoming si attendono -57 gradi), oltre 4mila voli sospesi in due giorni e persone senza corrente a causa delle basse temperature. Gli Stati Uniti aspettano il “bomb cyclone”, che potrebbe colpire circa il 60% del Paese

epa10376794 Passengers arrive to check in for their flights before a winter storm hits that threatens to close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Allarme maltempo negli Stati Uniti. La tempesta invernale che interesserà la maggior parte degli americani ha già causato nella giornata del 22 dicembre 2022 la cancellazione di oltre 2mila voli. Venerdì 23 dicembre ne sono stati cancellati altri 2.700, riferisce la Cnn

Usa, tempesta di neve e voli cancellati: New York dichiara lo stato d'emergenza

epa10376790 Passengers arrive to check in for their flights before a winter storm hits that threatens to close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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I forti venti, le abbondanti nevicate e il freddo renderanno il Natale gelido per milioni di persone, forse il più freddo degli ultimi 40 anni

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epa10376671 Passengers wait for their flights before a winter storm hits that threatens to close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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I meteorologi parlano di un evento climatico che si verifica una volta in una generazione: più di 90 milioni di americani in 37 Stati sono sotto l'allerta meteo e circa l'80% degli Stati Uniti potrebbe sperimentare temperature molto sotto lo zero, anche nel sud

Usa, tempesta di neve nel Midwest e allerta meteo: atteso freddo record

epa10376789 Passengers arrive to check in for their flights before a winter storm hits that threatens to close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Sono previste temperature glaciale ovunque con punte di -57 gradi in alcune zone montuose del Wyoming. E intanto, si legge su Cnn, sono state raggiunti già due record: -41 a Casper e -29 a Riverton

epa10376664 Passengers check in for their flights before the threat of a winter storm could close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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La Federal Aviation Administration ha rimandato i voli all'aeroporto nazionale Reagan di Washington, all'aeroporto internazionale di Philadelphia e agli aeroporti di Newark e John F. Kennedy nell'area metropolitana di New York

epa10376791 Passengers arrive to check in for their flights before a winter storm hits that threatens to close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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La Cnn riporta i dati del sito web PowerOutage.us, secondo cui più di 150mila clienti sono senza corrente in alcune zone del sud-est e del centro degli Stati Uniti, a causa dell'aria fredda e dei venti che attraversano la zona

epa10376793 Snow plows clear the roadway as passengers arrive to check in for their flights before a winter storm hits that threatens to close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Si prevede che le interruzioni di corrente aumenteranno, poiché il ripristino dell'energia elettrica sarà difficile in queste condizioni

epa10376649 Passengers wait in security lines after checking in for their flights before the threat of a winter storm closes down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Una bufera di neve potrebbe colpire Buffalo, vicino New York, e le comunità circostanti. In particolare l'Ohio dovrà affrontare una situazione "unica e pericolosa" per tutto il fine settimana di Natale, con condizioni di gelo improvviso che dureranno fino a questa mattina. L’avviso è arrivato dal governatore Mike DeWine

epa10376474 President Joe Biden issues warnings and travel advisories from the White House for the United States as a severe weather system threatens to impact most of the country in Washington D.C, USA, 22 December 2022. The weather system which is being called a 'Bomb Cyclone' threatens to disrupt travel and create life threatening conditions for large parts of the country over the December 25th Christmas Weekend. EPA/Jemal Countess / POOL

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Il presidente Joe Biden ha sottolineato come sia la tempesta sia il freddo negli Stati Uniti siano "pericolosi. Incoraggio tutti a seguite le indicazioni. Questo non è un giorno di neve come quando eravamo bambini, è una cosa seria"

epa10376792 Passengers arrive to check in for their flights before a winter storm hits that threatens to close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Il fenomeno atmosferico è stato infatti definito “Bomb cyclone”. Come ricorda la Cnn, il termine indica una tempesta in rapido rafforzamento che soddisfa determinati criteri. In genere, la pressione deve scendere di 24 millibar (un'unità di misura della pressione) entro 24 ore

epa10376672 Passengers check in for their flights before the threat of a winter storm could close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Questo parametro si basa però anche sulla latitudine della tempesta. Quindi, il requisito dei millibar può cambiare a seconda del luogo in cui quest’ultima si forma. Dai media americani è stato anche utilizzato il termine “snowmaggedon”

epa10376647 A board shows the status of flights before the threat of a winter storm could close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Il termine Bomb cyclone, prosegue la Cnn, si può far risalire a un articolo di ricerca meteorologica pubblicato in un'edizione del 1980 della Monthly Weather Review

epa10376663 Passengers check in for their flights before the threat of a winter storm could close down air traffic at O'Hare International Airport in Chicago, Illinois, USA, 22 December 2022. Much of the US is under a winter storm warning as an arctic cold front is expected to bring below freezing temperatures, snow, and ice to much of the central states areas. The storm is expected to snarl travel on one of the busiest travel days of the year. EPA/TANNEN MAURY

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Gli autori, i meteorologi del Mit Fred Sanders e John Gyakum, si erano basati sul lavoro del ricercatore svedese di meteorologia Tor Bergeron, che inizialmente aveva definito "tempeste in rapido approfondimento" quelle che – appunto, come detto – soddisfacevano il criterio dei 24 millibar in 24 ore

Le previsioni meteo in Italia