A deadly heat wave slowly boiling western Europe this month is being driven by a weather pattern often known as an Omega block, which scientists say could turn into more common around the globe — including in Canada.
The warmth wave has pushed temperatures as much as 18 C above their seasonal average, based on the Reuters Climate Monitor. Lots of of individuals have died, including at the least 40 in France who’ve drowned while swimming to flee the warmth, based on officials.
“Over the region studied, this heat wave is essentially the most severe ever recorded,” the World Weather Attribution group of climate scientists said in an evaluation Friday.
Here’s what to find out about an Omega block, and whether climate change is responsible.
An Omega block gets its name from how the pressure systems appear on a weather map, which resembles the Greek letter “Ω.”
In Europe’s case, a bulge of warmer high pressure has settled over the affected countries, with low pressures on either side of it — the Atlantic coast to the west, and parts of eastern Europe at the alternative end.
The hotter air gets stuck or “blocked” inside that structure, versus normal conditions where the jet stream carries weather systems from west to east.
“Since you’ve got this high pressure system sitting there within the centre, you will have a really stable and really warm air mass since the heat is moved northward into that area,” Gordon McBean, a professor emeritus in weather and environmental studies at Western University, said in an interview.
“Then it builds up over time.”
Omega blocks typically last between three and 10 days, but can sometimes persist for weeks.
Map showing the forecast maximum temperatures from June 25-27 in Europe.
Associated Press
What happens during an Omega Block?
Countries including Spain, France and Germany have been seeing hot and dry conditions. Since the high pressure also suppresses the formation of clouds, there’s been little relief from the sun.
France recorded its hottest-ever temperature of 43.8 C within the small southwestern town of Pissos on Wednesday.
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That day was the most popular day for the complete country on record, based on the Meteo France weather agency, which said the typical temperature measured at 30 French weather stations across day and night reached 30 C for the primary time ever.
Saarbruecken, a German city near the French border, broke the national temperature record on Friday at 41.3 C.
Regions within the low-pressure areas flanking the warmth wave, meanwhile, usually tend to see cooler, rainy conditions.
Britain has been been caught in the midst of the high and low pressure systems, with intense heat within the south and east and cooler temperatures within the north and west, based on the UK Met Office.
Still, forecasters prolonged a red alert for warmth Friday after the temperature in Suffolk, England, reached 37.3 C, marking the most popular June day the country has ever seen.
Can an Omega block occur in Canada?
Yes — and it’s already happened this 12 months.
Meteorologists on the Weather Network say an Omega block was chargeable for a late May heat wave in parts of Alberta, Saskatchewan and Manitoba. Much of the region saw highs reaching 35 C.
One other Omega block was also behind the record-smashing 21 C high that Saskatchewan reported in January 2024, the network said.
McBean said Omega blocks will be predicted with fairly high confidence before they occur, noting it’s one in every of several extreme weather patterns which are becoming more frequent in recent times.
What role does climate change play?
The World Weather Attribution evaluation said the European heat wave would have been “virtually inconceivable” without human-caused climate change.
The same heat wave in the identical month 50 years ago would have been around 3.5 C cooler than this one, the scientists said.
The evaluation added the past week’s high nighttime temperatures were 100 times more prone to occur than they’d have been 20 years ago.
That’s due to rising baseline of world temperatures made possible by greenhouse gas emissions.
The European heat wave can be occurring across the five-year anniversary of the deadly heat dome that scorched British Columbia and the Pacific Northwest of the U.S. in 2021, which saw greater than 600 deaths within the province alone.
McBean said it’s essential for people and officials to concentrate on the increasing frequency of such heat events and to organize accordingly.
“These are situations which are leading unfortunately to death (and) economic cost of serious amounts, and these are going to extend in the long run,” he said.
“We’d like to adapt our ways of coping with them,” he added, from improved warning systems to making sure homes and buildings are designed with cooling in mind.
—with files from the Associated Press and Reuters
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