UN Geneva - Multimedia Newsroom : UNOG Bi-weekly press briefing: Heatwave Alert

Record-breaking ‘pressure-cooker’ heatwave hits Canada, US northwest

A "pressure-cooker" heatwave that's broken temperature records twice in two days in the US northwest and western Canada shows no signs of abating, the World Meteorological Organization (WMO) said on Tuesday.

The scorching early summer conditions have been mirrored elsewhere in the northern hemisphere, from Eastern Europe to India, said Clare Nullis, spokesperson for the World Meteorological Organization (WMO).

“An exceptional and dangerous heatwave is breaking in northwestern United States of America and western Canada; this is obviously a part of the world which is more accustomed to cool weather. Temperature are likely to reach as high as 45 degrees Celsius by day for perhaps five or more days; so that’s …a very long spell, with extremely warm nights in between.”

The WMO official noted that the all-time Canadian temperature record was broken on Sunday in Lytton, British Columbia, which recorded a high of 46.6 degrees Celsius.

“This smashed the previous record – normally when you break a record, it’s by a small margin – this smashed the record by a full 1.6 degrees Celsius,” Ms. Nullis said.

Less than 24 hours later, on Monday, Lytton broke the record again, this time measuring 47.9 degree Celsius. “This to be underlined, it’s in the province of British Columbia, it’s to the Rocky Mountains, the Glacier National Park, and yet we’re seeing temperatures which are more typical of the Middle East or North Africa,” Ms. Nullis added.

Such extreme temperatures pose a major threat to people's health, agriculture and the environment “because the region is not used to such heat and many people do not have air conditioning”, WMO said in a statement which highlighted how important it was for national weather centres to issue early warnings to limit the death toll.

Citing Environment and Climate Change Canada meteorologist Armel Castellan, WMO noted that higher temperatures would likely peak early this week on the coast and by the middle of the week for the interior of British Columbia; afterwards, the baking heat is expected to move east towards Alberta.
“Yukon and North West Territories have recorded their all-time highest temperatures not just in June, but any point in the year. We are setting records that have no business in being set so early in the season,” said Mr. Castellan.

WMO’s Ms. Nullis explained that the extreme heat is caused by “an atmospheric blocking pattern” which has led to a “heat dome” trapped by low pressure either side.
“Normally you have the jet stream which is this vast high-moving belt of wind which …moves weather on, but it’s not happening this time...it’s almost like a pressure cooker effect and you’ve got very, very high heat.”

This heatwave follows another intensely hot period less than two weeks ago that baked the US desert Southwest and California, with hundreds of record highs.

Other parts of the northern hemisphere have also seen exceptional early hot summer conditions, including north Africa, the Arabian Peninsula, eastern Europe, Iran and the northwestern Indian continent.

Daily temperatures have exceeded 45 degrees Celsius in several locations and reached passed 50 degrees Celsius in the Sahara.
Western Russia and areas around the Caspian Sea have also seen unusually high temperatures, the result of a large area of high pressure.

Temperatures in the Moscow region are expected to reach mid-30 degrees Celsius by day and remain above 20 degrees Celsius at night, WMO said, while areas nearer the Caspian Sea are expected to experience temperatures reaching the mid-40s and remaining above 25 degrees Celsius.

“It is likely that some all-time temperature records will be set during this heatwave,” WMO said, underscoring the impact of human-induced climate change, which has resulted in global temperatures being 1.2 degrees Celsius higher than the pre-industrial levels.
ends

UNOG Bi-weekly press briefing: Heatwave Alert - WMO

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