- On a global average, the world has warmed about 1.8 degrees Fahrenheit since 1900. An extreme, ongoing heat wave in Western North America began affecting much of the Pacific Northwest and Western Canada since, late June 2021. Hundreds of deaths in British Columbia, Washington and Oregon have been linked to a heat wave that has roasted the Pacific Northwest for days and broken Canadian heat records, sending hundreds of thousands of people scrambling for relief.
- These temperatures being reported from the Pacific northwest and some parts of Canada are part of a “historic” heat wave, a result of a phenomenon referred to as a “heat dome”.
What is heat wave and heat dome?
- Heat waves begin when high pressure in the atmosphere moves in and pushes warm air toward the ground. That air warms up further as it is compressed, and we begin to feel a lot hotter. The high-pressure system pressing down on the ground expands vertically, forcing other weather systems to change course. It even minimizes wind and cloud cover, making the air more stifling. This is also why a heat wave parks itself over an area for several days or longer.
- Heat dome : The National Oceanic and Atmospheric Administration (NOAA) says that to understand what causes a heat dome, one should liken the Pacific ocean to a large swimming pool in which the heater is turned on. Once the heater is on, the portions of the pool close to the heating jets will warm up faster and therefore, the temperature in that area will be higher. In the same way, the western Pacific ocean’s temperatures have increased in the past few decades and are relatively more than the temperature in the eastern Pacific.
- This strong change in ocean temperature from the west to the east is what a team of scientists believe is the reason for the heat dome, which is when the atmosphere traps heat at the surface, which encourages the formation of a heat wave. To compare, the reason that the planet Venus is the hottest in the Solar System is because its thick, dense cloud cover traps the heat at the surface, leading to temperatures as high as 471 degree Celsius.