What is ‘bomb cyclone’ and why is it freezing USA?

Context:

  • As northern India shivers due to the prevailing cold wave, 8,431 miles away, in the United States of America, a ‘bomb cyclone’ is causing exposed skin to freeze within 30 minutes.
  • The United States East Coast and Midwest are battling record-breaking low temperatures as cold Arctic air continues to sweep through the region followed by the freezing winter storm — bomb cyclone or bombogenesis.
  • The winter storm has reportedly claimed at least 18 lives, including four in traffic accidents in North Carolina and three in Texas. According to reports, temperatures fell as low as -42 degrees Celsius across much of the eastern area. Authorities issued warnings saying there was an impending risk of frostbite. The cold weather disrupted flight services and caused power outages in tens of thousands of homes in the US.
  • The cyclone, scientists explained, is essentially a storm caused by a collision of warm air and cold air which develop into rotating storm-like pattern and lead to an explosive deepening of pressure. The East Coast’s first snowstorm of 2018 was energised by this rapid drop in barometric pressure.
  • A storm is considered a ‘bomb’ when the pressure drops rapidly — at least 24 millibars in 24 hours. Bomb cyclones also draw air from polar regions after it weakens. This explains the Arctic air freezing parts of US.

Source:TH