Extreme cold temperatures have been barraging the Eastern half of the United States since Thursday, February 19, covering the region in a blanket of snow. Now, the NASA satellite, Terra, with its Moderate Resolution Imaging Spectroradiometer or the MODIS instrument has captured the aftermath of the past few days in an image that showcases the once green landscape turned snow white.
The image was provided by NASA’s Goddard Space Flight Center in Greenbelt, Maryland which they took on Thursday, February 19 at 16:20 UTC (11:20 a.m. EST). The snow cover and chill arctic air, caused by what is known as the polar vortex, has always been associated with a colder winter. However, with Siberian air also rolling into the US, the temperatures of the Eastern United States were brought even lower.
The air flow from Siberia, called the cross-polar flow, moves in from the North Pole, and maintains its frigidity as it passes through the area’s tundras and ice-covered land, giving the air no chance to gain some more heat. Thus, several cities across the region have reached new temperature lows, which have broken records standing since the 1890s.
The polar vortex is a large pocket of very cold air that usually just hovers over the area of the Northern hemisphere. However, high pressure systems that reach over to the North Pole cause the polar vortex to move lower, bringing it down to the United States and Canada. When this phenomenon occurs, subzero temperatures in the affected areas are to be expected. It is only when these high pressure systems disappear that the polar vortex moves back to its intended area, bringing North America’s temperatures to a more normal level.
In Tennessee, a number of deaths have been already been attributed as a direct or indirect effect of the cold front, from hypothermia to delays in access of medical care due to frozen roads. These extreme temperatures will unquestioningly also affect the more sensitive vegetation, and can delay the coming of spring. Effects have also been noted on other states, especially in the Western half, where record highs for the season are being recorded. Northern Alaska, for example, reported to have temperatures 40 degrees higher than was normal at this time of the year.
NOAA’s NPC has stated that temperatures can be expected to normalize again after Friday. However, meteorological associations have forecasted to expect two more “cold blasts” within the month, since two more bouts of cold are expected to affect the US. These temperatures, however, will not be as extreme as those recently experienced.