The most at-risk regions in the world for high-impact heatwaves

Western North America heatwave, June 2021

In June 2021, western North America experienced a record-breaking heatwave. In Lytton, British Columbia, temperatures of 49.6 °C were observed on June 29th, breaking the previous record by almost 5 °C²⁸. The heatwave was associated with an unusual circulation pattern, with a blocking anticyclone leading to a stagnant warm air mass²⁹.

A rapid attribution study found the event was so far beyond what had been previously observed that it was deemed virtually impossible without climate change³⁰. In that study, the region assessed was chosen based on…