An image released by NOAA shows the formation of a heat dome.(Courtesy: oceanservice.noaa.gov)
An image released by NOAA shows the formation of a heat dome.(Courtesy: oceanservice.noaa.gov)

What is a heat dome? Extreme temperatures in Canada, US explained

Canada and parts of United States are experiencing extreme temperatures, due to which hundreds of people have died. The weather is due to heat dome, a climate phenomenon behind sudden rise in temperatures.
By hindustantimes.com | Written by Amit Chaturvedi, Hindustan Times, New Delhi
PUBLISHED ON JUL 01, 2021 10:09 AM IST

Canada is reeling under a severe heat wave, which has caused an unprecedented 195 per cent rise in sudden fatalities within the past five days, Chief Coroner Lisa Lapointe.

"Between Friday and 1 pm today, at least 486 sudden and unexpected deaths have been reported to our agency," Lapointe said in a statement.

The abnormal heat wave caused the temperature in the country to rise to 49.5 degrees Celsius, an all-time record. The weather experts have blamed the heat dome effect for the sudden rise in temperature.

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 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, it further said.

How long dies a heat dome last?

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.

Effects of heat domes

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. 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 destroys a lot of land area in the US every year.

Climate change and heat domes

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.

Apart from the US, cities as far north as the Arctic Circle broke heat records this week.

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