December 10, 2023

Syllabus- General Studies 1 (Geography)

Introduction to Disasters: Concepts, definitions, disaster classifications including natural

and man-made disasters.


Parts of North America, both in Canada and united states of America, are registering high temperatures across various regions

  • In Portland city in Oregon, US, temperatures as high as 46 degree Celsius were recently registered.
  • In Salem, barely 72 km away from Portland, the temperatures were highest at about 47 degree Celsius on June 28.
  • Canada too saw its highest temperature ever recorded in the country’s west. In Lytton in British Columbia, temperatures soared to over 46 degree Celsius last week.

These temperatures being reported from the Pacific northwest and some parts of Canada are part of a “historic” heat wave that lasted over a week, a result of a phenomenon referred to as a “heat dome”.

What is a Heat Dome?

  • According to National Oceanic and Atmospheric Administration (NOAA) of US department of commerce, a heat dome occurs when the atmosphere traps hot ocean(pacific ocean) air like a lid or cap.
  • The phenomenon begins when there is a strong change (or gradient) in ocean temperatures.
  • In the process known as convection, the gradient causes more warm air, heated by the ocean surface, to rise over the ocean surface, according to NOAA.
  • As prevailing winds move the hot air east, the northern shifts of the jet stream trap the air and move it toward land, where it sinks, resulting in heat waves.


  • Many weather scientists and organisations such as NOAA have studied these climatic changes and arrived at the conclusion that a heat dome typically lasts a week. They said that the formation becomes too bog to keep standing and falls over, releasing the trapped air and ending the swelter.





  • Those living without an air conditioner see the temperatures of their homes rising to unbearably high, leading to sudden fatalities like those which are being reported in Canada and parts of the US.
  • Some heat-related illnesses include heat stroke, heat exhaustion, sunburn and heat rashes. Sometimes, heat-related illnesses can prove fatal.
  • The trapping of heat can also damage crops, dry out vegetation and result in droughts, according to weather experts.
  • The sweltering heat wave will also lead to rise in energy demand, especially electricity, leading to pushing up rates.
  • The heat domes can also act as fuel to wildfires, which destroy a lot of land area in the US every year.

Link between Climate change and heat waves

Scientists who have been studying the climate tend to agree that the heat waves occurring today are more likely to be a result of climate change for which humans are responsible.

The weather scientists have been highlighting the effects of rising temperature (climate change) on more extreme heat waves. According to a 2017 NOAA survey, average US temperatures have increased since the late 19th century.

In decades to come, the climate scientists expect more days of severe heat wave.

Question- Write a short note on the phenomenon of Heat Domes and its harmful effects.



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