Heat dome causing heat wave in Pacific Northwest
The unprecedented heatwave is being attributed to the creation of a heat dome in the region, which has trapped heat and blocked other weather systems from moving in.
Published Date - 7 July 2021, 04:04 PM
The historic heat wave prevailing in the Pacific Northwest has reportedly led to hundreds of deaths in Canada, Oregon and Washington as scorching temperatures shattered all-time records. Oregon in the US reported 63 deaths linked to the heatwave while in British Columbia, at least 486 sudden deaths were reported over five days.
The unprecedented heatwave is being attributed to the creation of a heat dome in the region, which has trapped heat and blocked other weather systems from moving in. Read more about the phenomenon…
Heat dome
According to the US-based National Oceanic and Atmospheric Administration (NOAA), a heat dome is created when strong high-pressure atmospheric conditions combine with weather patterns like La Niña, creating vast areas of sweltering heat that get trapped under the high-pressure “dome”.
La Niña is a climate pattern when strong winds blow warm water at the ocean’s surface from South America to Indonesia. As the warm water moves west, cold water from the deep rises to the surface near the coast of South America.
Western Pacific’s temperatures have risen over the past few decades as compared to that of the Eastern Pacific, creating major pressure differences that drive winds across the entire ocean. The pressure change leads to warm air, heated by the ocean surface, rise over the western Pacific, and decreases convection over the central and eastern Pacific.
Is climate change behind heat dome?
It has been established that rising temperatures would lead to hotter weather and human-made climatic changes are leading to dangerous weather trends across the world. Heatwaves have been a regular phenomenon on land. However, global warming has caused them to be hotter with a longer duration and an increased frequency.
Effects of heat dome
Those living without an air conditioner see the temperatures of their homes rising to unbearably high, leading to sudden fatalities.
The trapping of heat can also damage crops, dry out vegetation and result in droughts. 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.
The ‘heat dome’
Occurs when the atmosphere traps hot ocean air like a lid or cap
1 In summer, the jet stream (which moves the air) shifts northward
2 Hot and stagnant air expands upwards
3 Strong and high-pressure atmospheric conditions combine with influences from La Nina act like: a dome or cap
4 In a process known as convection, hot air attempts to escape but high pressure pushes it back down
5 Under the dome, the air sinks and compresses, releasing more heat
6 As winds move the hot air east, the jet stream traps the air where it sinks, resulting in heat waves
The hotter the temperature is, the stronger the heat dome gets, and vice versa.
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