The 2021 Pacific Northwest Heat Wave Killed 868 People and Burned a Town to the Ground

In late June 2021, a heat wave of almost incomprehensible intensity descended on the Pacific Northwest. Portland, Oregon hit 116°F — breaking its all-time temperature record on three consecutive days. Seattle reached 108°F, a mark it had hit only three times in the previous 126 years, and then hit three days in a row. In British Columbia, a small town called Lytton recorded 49.6°C (121°F), breaking Canada's all-time national temperature record three days in a row. The day after setting that final record, much of Lytton burned to the ground.

A comprehensive scientific review published in Nature Communications in 2023 describes the event as unprecedented not only for its temperatures but for the scale and variety of its consequences. The authors catalogued human deaths, mass marine die-offs, crop failures, glacier melt, wildfires, and downstream landslides, all cascading consequences of a single catastrophic weather event that lasted roughly one week.

Records That Stunned Even Meteorologists

The temperatures were staggering even by the standards of more heat-accustomed regions. Portland's hottest three-day stretch averaged 112°F, beating its previous record by 6°F. Lytton's peak of 121°F exceeded any temperature ever recorded in Las Vegas, Nevada, despite being located more than 1,000 miles further north. According to NOAA's Climate Extremes Index, the portion of the Pacific Northwest experiencing extreme summer heat has dramatically expanded over the last 20 years.