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Power officials declare 'Level 1' emergency as heat wave sets record-high temperatures across states — here's what you need to know

The extreme heat might last for several days.

The extreme heat might last for several days.

Photo Credit: iStock

The year's first heat wave for the central and eastern United States has spread torrid temperatures and high humidity from Chicago to Boston. 

What's happening?

Record-setting heat has spread from the Midwest and Ohio Valley regions to the Mid-Atlantic and New England as a "heat dome" settles over the eastern half of the country. Chicago hit a high of 97 degrees on June 17 to break the daily record that was first set in 1887, per the Chicago Tribune. The scorching heat spread eastward the next day.  

This is not the first heat dome the U.S. has seen this year. It is still only early summer, but other heat domes have already been reported in the southern plains and desert southwest.

A heat dome is a persistent ridge of high pressure that settles over an area for an extended period, sometimes weeks, trapping heat and causing temperatures to soar to record-breaking levels. The air sinks and compresses under the high-pressure ridge, creating a bulging dome that can cover several states.

The most recent heat dome has expanded into New England, where the region's power grid operator declared a "Level 1" emergency when demand for power surged as people tried to cope with the oppressive heat and humidity. ISO New England Inc. serves more than 7 million customers spread out over six states. 

Why are heat domes so important?

A heat dome can persist for several days and lead to a heat wave, which can bring extreme heat and humidity to the surface. The National Weather Service defines a heat wave as "a period of abnormally hot weather generally lasting more than two days." Heat waves can bring a variety of heat-related illnesses, including those that can kill in the worst cases.

Heat is the No. 1 weather-related killer in the United States. The Centers for Disease Control and Prevention recorded 2,300 heat-related deaths last year, the highest total in 45 years of records.

Several scientists think deaths from heat are undercounted. A study by Texas A&M University estimated there were nearly 11,000 heat-related deaths in 2023.

What's being done about extreme heat from heat domes?

Our world is getting warmer as heat-trapping gases build in the atmosphere. This change in our climate is making heat waves more frequent and intense. Heat waves strain our health along with power grids. Reducing carbon pollution can help cool the planet.

Weatherizing our homes and switching to LED lightbulbs (which give off much less heat than incandescent bulbs) are just two examples of ways we can reduce toxic gases by changing how we use electricity while also combatting high temperatures in our homes.

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