GENEVA, Feb. 1 (Xinhua) -- The month of January has been marked by high impact weather in many parts of the world, including dangerous and extreme cold in North America, the World Meteorological Organization (WMO) said Friday in a news release.

Large parts of North America have been gripped by an influx of Arctic air. Combined with gusty winds, this is producing dangerous wind chills across a significant portion of the Upper Midwest into the Northeast U.S., said WMO.

The frigid airmass is also supporting heavy lake effect snows downwind of the Great Lakes. The U.S. National Weather Service said that temperatures will be well below average over the Upper Mississippi Valley, Great Lakes, into parts of the Northern Mid-Atlantic. The national low temperature record was measured at minus 48.9 degrees Celsius.

According to the WMO, the bitterly cold temperatures are caused by the influence of the Polar Vortex, which is a large area of low pressure and cold air surrounding the North Pole, with strong counter-clockwise winds known as the jet stream that trap the cold around the Pole.

Disturbances in the jet stream and the intrusion of warmer mid-latitude air masses can alter the structure and the dynamics of the Polar Vortex, sending Arctic air south into middle latitudes and bringing warmer air into the Arctic.

"The cold weather in the eastern United States certainly does not disprove climate change," said WMO Secretary-General Petteri Taalas. "Frigid temperatures and snow will continue to be part of our typical weather patterns in the northern hemisphere winter."

The WMO chief added that as Arctic has faced a warming, which is twice the global average and caused a large fraction of the snow and ice in the region to have melted, the changes there are affecting weather patterns outside the Arctic in the Northern Hemisphere.

"A part of the cold anomalies at lower latitudes could be linked to the dramatic changes in the Arctic," he said, and "what happens at the poles does not stay at the poles, but influences weather and climate conditions in lower latitudes where hundreds of millions of people live."

During the past month, eastern U.S. and parts of Canada were seeing record-breaking cold temperatures, but Alaska and large parts of the Arctic have been warmer than average.

Meanwhile, extreme weathers were also record in other parts of the world, such as the record heat and wildfires in Australia, high temperatures and rainfall in parts of South America, and heavy snowfall in the Alps and Himalayas. Enditem

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