According to the German Weather Service (DWD), a severe heat wave in Canada, which has lasted for several days, is an “unprecedented event” since the start of weather records. Although it is not unusual in itself that heat waves can also occur in the North American country, meteorologist Sebastian Schapert told the German Press Agency on Friday. Still, the current situation is not typical: “Based on the fact that the new record values have only now been measured there, it is already clear that the heat wave currently occurring is a very extreme event.”
The Canadian city of Lytton was almost completely destroyed after the fire broke out on Wednesday evening (local time). The community, which is about 260 kilometers northeast of Vancouver, had previously recorded three consecutive days of heat. According to the weather agency, the thermometer recorded 49.6 degrees Celsius on Tuesday, the highest temperature ever recorded in Canada.
Scheppert attributes the heat wave in Canada primarily to the fact that warm air from the subtropical regions moved north and remained submerged there for several days. The additional solar radiation caused the temperature to rise higher and higher and the air became dry.
DWD experts compare the extreme weather event with a so-called omega weather condition: It creates a strong high that hits the westerly wind and blocks it, Schapert said. “Any deep trough just doesn’t get ahead, everything stops.” According to Shappert, this high pressure area is surrounded by two lows that form to the west and east of this high pressure bell and stabilize the system. In this way, an area of high pressure can persist for a long time, sometimes even several weeks.
According to the DWD, the flow area that surrounds the high pressure area looks like the Greek capital letter Omega. In Germany, Omega weather conditions cause persistent heat, especially in the summer months of 2018, 2019 and 2020.
