2021 Heat Dome Was a 'Near Miss,' Simon Fraser Study Argues

In 2021 the script flipped: a major city escaped mass ignition, but the heat wave's aftermath stayed hot and dry, feeding out-of-control fires that destroyed Lytton.

Why call 2021 a near miss?

"The wildfires of 1941 are the main reason I've now reinterpreted 2021 as being a near miss," said Anderson, who works in SFU's School of Environmental Science. "You can imagine a future heat wave that could very plausibly initiate many wildfires around Vancouver, like 1941, and then amplify them with post–heat wave fire weather, as in 2021."

In other words, the region has already experienced both halves of a worst-case scenario — mass ignition around a major city in 1941, and fire-amplifying weather after the heat in 2021 — just never in the same summer.

"The 1941 event is the most direct and maybe the only comparison to the 2021 heat wave, considering its magnitude, extent, location and timing," Anderson said. "Both 1941 and 2021 were similarly shocking in their severity. But 1941 had a significantly different impact... It essentially left Vancouverites trapped between water to the west and fires everywhere else."

How did the death tolls differ?

Around 350 deaths were attributed to the 1941 heat wave at the time, either directly through heatstroke or indirectly, mostly by drowning. Most of those deaths occurred in eastern North America, because the 1941 heat wave migrated east across the continent while the 2021 heat dome stayed parked over the west.

"The reported geographical spread of deaths in 1941 suggests that the increased humidity and population density in the East could have been factors," Anderson said. "In some ways, the fact that the 2021 heat dome did not persist in the East means we may have avoided an even higher death toll."

What can planners take from this?

The study's release coincides with the fifth anniversary of the 2021 event, and Anderson frames the pair of heat waves as a working dataset for how impacts shift as the climate warms. His conclusion is less fatalistic than it sounds.

"Heat waves are climate events, as well as social and cultural events, meaning that their impacts are in part determined by the world that we choose to build," he said.

One detail from the archives surprised him: even in the middle of World War II, the 1941 heat wave pushed the war off the front pages. "It overtook the war as being the topic of conversation," Anderson said. "The coverage really paints this picture of an event that was really recognized as being meaningful at the time that it happened."

A society that took a heat wave that seriously in 1941, he implies, has little excuse in 2026.

The paper — Sam Anderson et al., "Extreme North American heatwaves in 1941 and 2021 drove widespread but contrasting impacts" — appears in Communications Earth & Environment (DOI: 10.1038/s43247-026-04055-0).