U.S. heat domes could have stormy impacts in Canada. What to expect this summer

A “heat dome” has settled over parts of the western U.S., with excessive heat warnings in effect for millions. While it’s yet to be seen if those temperatures will hit Canada, meteorologists and scientists say the country could still see an impact, likely in the form of storms.

A heat dome is caused by a strong ridge of high pressure that traps warm air underneath it. The ridge acts like a dome, giving it its name, and allows the sun to crank up the heat below and create a heat wave.

“These pressure systems move usually from west to east across the country, (but) occasionally, you can get a situation as a region of high pressure becomes stationary,” University of Toronto Mississauga atmospheric physics professor Kent Moore told Global News.

“For a period of days, or even a week or so, you get these persistent high pressures (and) it gets hotter and hotter and hotter.”

The systems can be deadly, causing hundreds of deaths in B.C. in 2021, and more recently, dozens of heat-related deaths in Mexico last month.

Even if the dome over the U.S. doesn’t move into Canada, the bubble that it creates could still contribute to stormy conditions north of the border.

Jennifer Smith, a national warning preparedness meteorologist with Environment Canada, told Global News that when these domes become “anomalously large,” they can have wide-reaching effects, though it relies on weather systems to already be present.

“It’s really just that they can’t traverse through the ridge and so they’re forced around it and they follow this boundary,” Smith said. “If storms were to form, they would be ushered around this ridge.”

She stresses that while storms could be active in Canada due to such heat domes, the key is the formation of storms.

“Just because