Bomb Cyclone

In News

• Recently, an intense blizzard or snowstorm is wreaking havoc across the United States and Canada.
  • Forecasters have termed the blizzard as different from the usual weather events and called it a “bomb cyclone.” 

More about the news

• Location:
  • The scope of the storm has been nearly “unprecedented”, stretching from the Great Lakes near Canada to the Rio Grande along the border with Mexico. 
• Situation led by the blizzard/ bomb cyclone:
  • About 60% of the US population faced some sort of winter weather advisory or warning, and temperatures plummeted drastically below normal in major areas of the country.
  • More than 30 people confirmed dead so far in the US, and four people dead in Canada after a road accident on an icy path.

More about the Bomb Cyclone

• Formation:
  • Storms can form when a mass of low-pressure air meets a high-pressure mass. The air flows from high pressure to low, creating winds. 
    • The current bomb cyclone in the US happened when warm air from the gulf of Mexico collided with the cold arctic air. 
  • What makes it a bomb cyclone? Or Bombogenesis.
    • What defines a bomb cyclone is how rapidly the pressure drops in the low-pressure mass by at least 24 millibars in 24 hours. 
    • This quickly increases the pressure difference, or gradient, between the two air masses, making the winds stronger. 
    • This process of rapid intensification has a name: bombogenesis.
• Direction & continuation of the current cyclone:
  • As the winds blow, the rotation of the Earth creates a cyclonic effect. 
    • The direction is counterclockwise in the Northern Hemisphere (when viewed from above).
  • As the area where the two air masses meet moves northward and eastward, conditions for bombogenesis should continue moving as well.
• Outcomes of the Cyclone:
  • While this kind of storm is not exceedingly rare, this one is very strong, with high winds that are bringing heavy snow or rain to many areas.
  • Air pressure dropped to at least 962 millibars, while elsewhere it was as high as 1,047 millibars which is a really sharp gradient.
  • This has led to the development of extreme storm conditions near the core of the low-pressure system, with particularly harsh conditions.
• Predictions of dissipation:
  • Forecasts have called for above-average temperatures across most of the country next week.
  • But as the Arctic air spreads over most of the country it will eventually warm, reducing the pressure difference. The storm will dissipate. 
• Precautions:
  • US National Weather Service has warned people against travelling. 
    • It said such cold conditions can easily cause frostbite, and in cases of longer exposure, hypothermia and death.
  • Those who will be travelling by road will need to exercise particular caution, as visibility will be affected.
  • Those indoors have also been told to maintain safety precautions, such as charging electronic devices and keeping torches ready. 
    • Apart from wearing the appropriate layers of clothing, it was also advised that those working outside keep taking breaks to avoid exertion or health issues.
• May become frequent phenomenon:
  • Climate campaigners say global warming is likely to make bomb cyclones more frequent and intense.

Source: IE