Record-Breaking Heat Dome Settles over US Midwest, South

Aug 23, 2023

How Heat Domes Work

A bubble of high pressure, dry air, and stifling heat has formed over the US. This bubble is commonly known as a “heat dome.” It is inflicting dangerous, record-high temperatures on regions from Texas to Montana to Ohio.

The dome formed late last week. It originated in the Deep South. It is tying or eclipsing daily heat records in various cities. Alexandria, Louisiana, reached 110 degrees Fahrenheit on Saturday. College Station, Texas, hit 112 degrees on Sunday. 

The heat dome is spreading northward. It's smashing heat index marks as it travels. The index measures the “feels-like” temperature. How? By accounting for both air temps and humidity levels. Sioux City, Iowa, reached a heat index of 122 degrees Monday. Miami, Oklahoma, hit 126.7. That’s a state record. And on Saturday in Falls City, Nebraska, residents endured a scorching 128 degrees.

The National Weather Service (NWS) on Tuesday issued heat warnings for 22 states. NWS advised over 100 million people to take precautions.

The NWS released a midweek forecast. It said that temperatures and heat indices will reach levels that will pose a health risk. NWS also warned that such extreme heat will be potentially deadly to anyone without effective cooling and/or adequate hydration. The NWS reminded the public that heat is the number one cause of weather-related deaths in the US.

At least 11 heat-related deaths have been reported in the US in the past two weeks. This data comes from Axios. A further 3,836 calls have been issued to emergency medical services. These calls have been for heat-related illnesses and trauma over that period.

The heat dome is expected to persist through the weekend. This raises the probability that August will match, or exceed, July 2023 as the hottest month in recorded history. 

Reflect: Would you rather deal with extreme heat or extreme cold? Explain.

According to the infographic, which is necessary for a heat dome to form? (Common Core RI.5.7; RI.6.7)
a. wildfires
b. low pressure
c. clouds
d. high pressure
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