The United States went from summer temperatures to a harsh winter in 48 hours!
If December was marked by numerous heat records in the United States, these first days of January mark the transition to extreme winter conditions: in Texas, the weather service recorded a temperature difference of 40°C in just two days!
The United States is currently facing the first real winter offensive since the beginning of the season: a snowstorm is sweeping the country from west to east, before a second similar storm expected between this Wednesday and Friday. But, despite the heavy snowfall and the generalized chaos in transportation, it is finally the dizzying drop in temperatures that is the most striking.
From hot summer to freezing winter in just two days
December 2021 weather in North America was historic, with temperatures in many states more than 20 degrees above seasonal averages. In early December, temperatures were 25°C in the usually frigid Northwestern state of Montana and over 30°C in California and Texas. This exceptional weather situation, which encouraged the development of fires in the middle of winter, continued into early January. The state of Colorado suffered a major disaster, with the most destructive fires the state has ever seen (more than 1,000 homes destroyed) on December 30. The average temperature was around 10 degrees Celsius in the Denver area on the day of the fires, before dropping to -18 degrees Celsius two days later as a storm passed through, covering the ashen buildings with 20 centimeters of snow.
Even more impressive was the dramatic thermal contrast in Texas: the southern U.S. state went from a furnace worthy of August to frigid weather worthy of a northern state. From an average of 30 to 35°C in South Texas on the afternoon of January 1st (against an average of 21°C at that time) to negative temperatures (from -1 to -11°C) on the morning of January 3rd! That is a difference of 40 degrees over the same area in the space of two days. In the northwest, temperatures dropped to extremely low levels, without breaking any records, to -40°C in Montana on January 3. The ripples of the Jet Stream, which was too far north to let the cold sink during December, finally plunged southward, allowing a mass of arctic air to pass over the country. This classic winter pattern arrived much later than usual and marks a radical change from the much more unusual pattern of last December.
Two Snowstorms in One Week
The first real snowstorm of the winter is finishing its journey across the United States from west to east on Wednesday, after knocking out power to 850,000 homes, causing about 600 pileups on the roads and leading to the cancellation of over 2,000 flights. With 35 centimeters of snow, the capital Washington was completely paralyzed between Sunday and Monday. While the cold air mass resists over the northern half of the country, a second snowstorm is sweeping the country from this Wednesday until Friday. With a path further south, over less prepared states, the consequences will again be significant on transportation.
According to the latest seasonal forecast from Weather Underground, the weather extremes should still be very marked during the month of January in the United States: the north of the country (Washington, Montana, North Dakota, Minnesota) should remain cold and well below seasonal averages, while the south (Texas, Louisiana, Mississippi, Alabama, Georgia, Florida) should be unusually warm.