2021 heat dome linked to climate change, could become once-in-10-year event: study

The heat dome, which hit western Canada and the U.S. at the end of June and beginning of July is believed to be responsible for more than 600 deaths.

A new study suggests the deadly 2021 heat dome that hit B.C. and the U.S. Pacific Northwest was amplified by climate change and could become a once-in-10-year event if global temperatures aren’t kept below 2 C above the pre-industrial average.

The study, which was published this month in the journal Nature Climate Change cites the interaction between factors, including climate change, atmospheric weather patterns and dry soils in the region as factors that allowed the heat wave to reach extreme levels.

The heat dome, which hit western Canada and the U.S. at the end of June and beginning of July is believed to be responsible for more than 600 deaths, set national temperature records and preceded the fire that razed the community of Lytton to its foundations.

Study co-author and Columbia University PhD candidate Sam Bartusek said he and his team built a statistical model using temperature records dating back seven decades to come to their conclusions.

“Just a few decades ago … it’s estimated that this event would have been virtually impossible, so at a way lower probability of happening, but then because of the warming, since then it’s its likelihood as it has increased drastically,”

“And so we presently estimate that it’s about a one in 200-year event … One of the implications is that if temperatures rise to two degrees above pre-industrial conditions, the estimated likelihood of this of an event of this magnitude is about one in ten every year.”

Bartusek’s team looked at how a “wavy” pattern in the jet stream — disrupted from its usual east-west flow to a north-south flow — and another “wavy” atmospheric pattern coming off the Pacific Ocean reinforced one another in order to allow an “unprecedented atmospheric ridge” to stall over the west coast for days, setting up the heat wave.

They then looked at dry soil and surface temperature interacting with that ridge, which they found could increase the likelihood of “month-long high-temperature anomalies.”