“Our analysis showed that the warmth of the air column within the blocking system was in the top 0.01% of all events along the same latitude in the past half a century.”

“But this was an extraordinarily strong blocking event,” said Neal. The result was a warm, stagnant column of air that made it difficult for surface heat to escape to the upper atmosphere as it normally does.īlocking systems are well known for causing heat waves in the mid-latitudes, explained Emily Neal, a UChicago undergraduate student in environmental science and first author on the paper. A blocking anticyclone acts like a blanket, trapping heat in a region. These are known as “blocking” systems because they disrupt the normal eastward movement of weather systems. Then, as the cyclone moved slowly away, it triggered the formation of an anticyclone to the east-a system that rotates slowly around a center of high pressure instead of low. (Think of the spiral clouds you see during hurricanes.) When clouds form out of water vapor, the process actually releases heat, which accumulated in the atmosphere.

Cyclones are large, spiral-shaped systems that form around a center of low pressure. They found that in the week prior, a cyclone had formed over the Gulf of Alaska. Using data collected from satellites and on the ground, UChicago scientists set out to re-create the sequence of events. Before it was over, a town in Canadian British Columbia tied Death Valley for the highest temperature ever recorded in North America – 121 degrees Fahrenheit.īut the conditions had been set in motion weeks before. Streetcar cables melted in Portland, Oregon pavement buckled across the region. Previous record high temperatures shattered one after the other, by huge margins. The scientists hope this approach can help lay out why extreme events happen, and to better understand the odds of future events. Noboru Nakamura to lay out the mechanisms behind large-scale atmospheric weather. It also serves as a proof of concept for a comprehensive set of diagnostics developed by UChicago Prof. The account may shed light on the likelihood of such extreme heat waves in the future.

Last summer, a deadly wave of heat struck the Pacific Northwest, causing temperatures to soar more than 30 degrees Fahrenheit above normal and killing more than a thousand people.Ī new study has uncovered the sequence of events that precipitated the disaster, providing information that could further our understanding of heat formation on the North American continent.īy reviewing large-scale weather conditions and formations before the heat wave, University of Chicago scientists discovered that a cyclone spawned an “anticyclone,” which combined to produce and then trap heat near the surface of the region.

Heat wave pacific northwest