Heat Dome: what’s Causing the Unbelievably Hot Heatwave in the Pacific Northwest?

If you haven’t lived under an air-conditioned cliff for the past week, you’ll probably be aware that an extreme heatwave hits the Pacific Northwest, with huge parts of the U.S. and Canada suffering from intense heat. Canada set a record temperature of 47.9 degrees Celsius (116 degrees Fahrenheit) on Monday, while the U.S. National Weather Service issued extra heat warnings in most parts of Washington, Oregon, Montana and Idaho. For mild conditions in one part of North America, the intensity of the heat has reached deadly proportions, forcing many cities to open shelters for “cold centers” and killing dozens.

With temperatures so unbelievably high, many experts predicted this week’s weather that they suspected something was wrong with their models. “The predictions seemed completely foreign,” Larry O’Neill, an associate professor at Oregon State University and a state climate expert in Oregon, told NBC News. “They were so crazy that professional forecasters and people like me thought there must be something wrong with the models.”

Behind this unprecedented heatwave is a weather event known as the Hot Domb. It has a high-pressure system that is parked northwest of the Pacific Ocean, captures very warm air and prevents any cool marine air from entering like a bubble saucepan with ping pong. The high pressure also pushes the warm air down towards the soil and compresses it to make it warmer. According to the National Oceanic and Atmospheric Administration (NOAA), North America has the potential to create heat domes in North America in the years to come – such as 2021 – in the eastern Pacific when the waters are cooler and warmer in the western Pacific Ocean the following winter.

This difference in temperature creates air that pushes the heated air eastward toward North America. Eventually, the warm air gets stuck in the jet flow, the current of the wind moves clockwise around the earth, and the Pacific Ocean pushes towards the land in the northwest. Scientists often hesitate to link short-term weather events directly to the wider human-driven climate crisis. However, many are already speculating that such freak heatwaves may become increasingly common and more extreme as global temperatures continue to rise due to climate change.