The north-western seaboard of the United States has been experiencing record-breaking temperatures in the months of June and July due to a powerful heatwave that hit the country, leaving dozens of people dead and hundreds in search of shelter with a lower temperature.

But what is a heatwave?

The definition of a heatwave can differ in different regions but is normally considered as a period with substantially high temperatures. In the north-eastern parts of the United States, a heatwave is called three consecutive days with temperatures hitting the 90 degrees mark, according to reports from the New York Times.

Also Read: Record-breaking heatwave killed a billion sea animals off Canada’s coast

What can lead to a heatwave?

Under normal circumstances, a heatwave will be triggered when the atmospheric pressure rises above the ground and pushes warm air towards the earth. Due to the active pressure inflicted from the atmosphere on the warm air, it tends to increase in temperature making the surface of the earth even hotter.

The continual force exerted by the atmosphere, which creates increased pressure, provides the heatwave a direction leading it to expand vertically. Due to this climatic phenomenon, a heatwave generally tends to stick around a particular area for a prolonged duration, according to reports from the New York Times.

Also Read: Death Valley in California records highest temperature in at least 90 years

Heat Dome: All we know so far

As the name suggests, a heat dome is a high-pressure area that positions around an area like a lid over a pot. A difference in the temperature of the eastern and western pacific areas triggers the movement of dense, tropical, western air eastward. According to reports from the US National Oceanic and Atmospheric Administration, a La Nina year, such as 2021, is likely to witness such an atmospheric reaction. 

Both heat waves and domes are phenomena that have the potential to cause severe consequences like droughts, wildfires, shortage of resources and medical conditions such as hyperthermia, which killed multiple people in both the United States and Canada in the past month.