Authorities in Canada and the United States have urged people to stay indoors and cool off from the deadly heat.
As of Monday, nearly 70 deaths were reported in the Canadian province of British Columbia. These deaths, especially among the elderly, are associated with historic heat.
Heating domes are more common in the United States, but they are very early this year, says meteorologist William Huizinga of Buienradar. “Normally they emerge at the end of July. You don’t see that in June.”
Climatologist Van Oldenborgh says the situation in North America is unique. “You have a climate on this west coast where the summers are always hot and dry. But what is happening in terms of temperatures right now is way outside of normal.”
How is a heated dome formed?
A thermal dome is created as a result of a vicious cycle. A high pressure zone heats it as the air descends. This descent heats the air and dries it up. All the moisture that is still in the clouds disappears through this dry air.
Meteorologist William Huizinga explains, “No moisture in the clouds means no rain. No rain also means no moisture in the soil. Without rain or moisture in the soil, the sun has carte blanche. It continues. then to heat the air. And so on. the vicious circle continues. “
Since the air also expands and is therefore continuously heated, this air also remains at one place in this high pressure area. This actually creates a blockage of this high pressure area with hot air and therefore a kind of “dome” of heat.
According to Huizinga, the extreme heat is most noticeable on thermal domes. “50 degrees in Canada, it’s just weird. I think with climate change you’re going to see extremes like this more often.”
Van Oldenborgh cites climate change as one of the causes of the extreme temperatures in recent times. He says there are several possible causes. The effects must also have played together to cause such a sudden change in temperature.
“Normally weather records are broken by tenths of a degree, not whole degrees. We have already analyzed a number of heat waves. In practice, this is more difficult than you might think. heat are not only sensitive to climate change but also to other causes, such as drought, irrigation, air pollution and urbanization, so we want to study this carefully. ”
Van Oldenborgh cites heat waves as one of the deadliest consequences of climate change. According to him, the effect they can have is still largely underestimated.
“Last year we had heat in the Netherlands for a week with temperatures above 30 degrees, not even so extreme. Two weeks later, figures from the Central Bureau of Statistics showed that 600 people from more than usual had died during that time. If 600 people had died in a flood, it would make headlines for a week. “
In the Nederlands
But can temperatures as extreme as in North America also occur here? Not at the moment, says Huizinga, but adds that nothing is impossible.
“We are at a moderate latitude, such temperatures will not happen here very quickly. The only times we go above 40 degrees, the air is coming from North Africa and other factors must also be correct. But that that seems impossible now may be completely different for a while.
Fortunately, for people in Canada and the United States, it will be cooler in the next few days. “From today, the sea breeze in the coastal region should provide cooling,” says Van Oldenborgh.
“Monday and Tuesday were the worst days and unfortunately this will continue indoors for a while. But in the bigger cities the worst really has to be over now.”