What is the exceptional “heat dome” hitting Canada
Environment — di Andrea Barolini
The “heat dome” causing extraordinary temperatures in Canada is a well-known meteorological phenomenon, but one that is being worsened by climate change.
What is the exceptional “heat dome” hitting Canada
The “heat dome” causing extraordinary temperatures in Canada is a well-known meteorological phenomenon, but one that is being worsened by climate change.
The exceptional heatwave hitting the western portion of Canada has caused the sudden death of 486 people. This was announced on Wednesday 30 June by the authorities of the North American nation, who attributed the deaths to the totally abnormal temperatures recorded from Friday 25 June onwards in numerous locations.
How a "heat dome" works
In addition to the absolute record of 49.5 degrees Celsius reached in Lytton, the mercury came close to 48 degrees in Vancouver and exceeded 46 degrees in Portland (in Oregon, United States). In Seattle, temperatures also reached 41.6 degrees. All of this is attributed to what is known as a "heat dome".
Graphic explaining the 'heat dome', which occurs when the atmosphere traps hot ocean air like a lid or cap, and combined with other weather changes, leads to heat waves #AFPgraphics
A mass of hot air, starting from Mexico, moved northwards, where it encountered anticyclonic conditions that allowed it to remain in place. This triggered a meteorological phenomenon called subsidence, which involves the vertical descent of hot air from above, causing a compression of the air at ground level and raising its temperature.
Exceptional temperatures in Canada and the United States
The hot air, therefore, precisely because of the high pressure, cannot "escape" from the dome, but is instead pushed downward, effectively trapping the exceptional heat. This is a mechanism well known to meteorologists, but what is extraordinary in this case is its duration and intensity.
The normal temperature for this time of year in a city like Vancouver is in fact just above 20 degrees. But what is also striking is the fact that at the Whistler ski resort, according to Canada's meteorological service, temperatures reached 42 degrees.
The "heat dome" may not move until the end of the week
A further cause for concern is that the "heat dome" is expected to remain in place until the end of the week. Only at that point are winds blowing from westerly directions forecast to arrive, and these should push the hot air towards the central and eastern portions of Canada. Until then, however, the vicious cycle triggered by the phenomenon could even intensify.
I didn't think it was possible, not in my lifetime anyway.
+49.6°C in Canada 🇨🇦 That is 121°F!
This is the story of the Canadian heat record that was crushed on 3 consecutive days by an unfathomable margin of +4.6°C (+8°F).
This moment will be talked about for centuries.
+49.6°C in Canada 🇨🇦 That is 121°F!
This is the story of the Canadian heat record that was crushed on 3 consecutive days by an unfathomable margin of +4.6°C (+8°F).
This moment will be talked about for centuries.
Everything is further compounded by climate change. Although climate change is not the underlying cause of "heat domes", global warming raises the Earth's average temperature and makes extreme weather events increasingly frequent and severe.