What is a heat dome? Explaining the weather phenomenon baking large parts of US
William Gallus, Professor of Atmospheric Science, Iowa State University
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The first day of summer 2022 brought soaring temperatures across a large part of the United States. National Weather Service
A heat dome occurs when a persistent region of high pressure traps heat over an area. The heat dome can stretch over several states and linger for days to weeks, leaving the people, crops and animals below to suffer through stagnant, hot air that can feel like an oven.
Typically, heat domes are tied to the behavior of the jet stream, a band of fast winds high in the atmosphere that generally runs west to east.
Normally, the jet stream has a wavelike pattern, meandering north and then south and then north again. When these meanders in the jet stream become bigger, they move slower and can become stationary. That’s when heat domes can occur.
When the jet stream swings far to the north, air piles up and sinks. The air warms as it sinks, and the sinking air also keeps skies clear since it lowers humidity. That allows the sun to create hotter and hotter conditions near the ground.
If the air near the ground passes over mountains and descends, it can warm even more. This downslope warming played a large role in the extremely hot temperatures in the Pacific Northwest during a heat dome event in 2021, when Washington set a state record with 120 degrees Fahrenheit (49 Celsius), and temperatures reached 121 F in British Columbia in Canada, surpassing the previous Canadian record by 8 degrees F (4 C).
Heat domes involve high-pressure areas that trap and heat up the air below. NOAA
The human impact
Heat domes normally persist for several days in any one location, but they can last longer. They can also move, influencing neighboring areas over a week or two. The heat dome involved in the June 2022 U.S. heat wave crept eastward over time.
On rare occasions, the heat dome can be more persistent. That happened in the southern Plains in 1980, when as many as 10,000 people died during weeks of high summer heat. It also happened over much of the United States during the Dust Bowl years of the 1930s.
A heat dome can have serious impacts on people, because the stagnant weather pattern that allows it to exist usually results in weak winds and an increase in humidity. Both factors make the heat feel worse — and become more dangerous — because the human body is not cooled as much by sweating.
The heat index, a combination of heat and humidity, is often used to convey this danger by indicating what the temperature will feel like to most people. The high humidity also reduces the amount of cooling at night. Warm nights can leave people without air conditioners unable to cool off, which increases the risk of heat illnesses and deaths. With global warming, temperatures are already higher, too.
Heat can foster fun summer activities, but the body shouldn't be too hot for too long, as too much heat can harm your brain and other organs, according to the US National Institutes of Health. Sweating is the body's natural cooling system, but when that's not enough, there's increased risk for developing the heat-related illness hyperthermia — signs of which include heat cramps, heat edema and heat stroke.
Staying cool can be done by using some basic supplies and knowing how to manipulate your home to control its temperatures.
Heat can foster fun summer activities, but the body shouldn't be too hot for too long, as too much heat can harm your brain and other organs, according to the US National Institutes of Health. Sweating is the body's natural cooling system, but when that's not enough, there's increased risk for developing the heat-related illness hyperthermia — signs of which include heat cramps, heat edema and heat stroke.
Staying cool can be done by using some basic supplies and knowing how to manipulate your home to control its temperatures.
When you're hot and flushed, hydrating yourself is the first and foremost step to cooling down, said Wendell Porter, a senior lecturer emeritus in agricultural and biological engineering at the University of Florida.
The temperature of the water doesn't matter since your body will heat it, he added. If your body is suffering from the heat and needs to cool itself, it can't do that without enough moisture, since the body cools itself by sweating.
When you're hot and flushed, hydrating yourself is the first and foremost step to cooling down, said Wendell Porter, a senior lecturer emeritus in agricultural and biological engineering at the University of Florida.
The temperature of the water doesn't matter since your body will heat it, he added. If your body is suffering from the heat and needs to cool itself, it can't do that without enough moisture, since the body cools itself by sweating.
Taking a cold shower or bath helps cool your body by lowering your core temperature, Porter said.
For an extra cool blast, try peppermint soap. The menthol in peppermint oil activates brain receptors that tell your body something you're eating or feeling is cold.
Taking a cold shower or bath helps cool your body by lowering your core temperature, Porter said.
For an extra cool blast, try peppermint soap. The menthol in peppermint oil activates brain receptors that tell your body something you're eating or feeling is cold.
Place a cold washrag or ice bags (packs) on your wrists or drape it around your neck to cool your body. These pulse points are areas where blood vessels are close to the skin, so you'll cool down more quickly.
Shutterstock via CNN
Place a cold washrag or ice bags (packs) on your wrists or drape it around your neck to cool your body. These pulse points are areas where blood vessels are close to the skin, so you'll cool down more quickly.
Place box fans facing out of the windows of rooms you're spending time in to blow out hot air and replace it with cold air inside.
If the weather in your area tends to fall between 50 and 70 degrees Fahrenheit in the mornings and evenings, opening the windows on both sides of the house during those times can facilitate a cross-flow ventilation system. If you do this, you can opt to use or not use the fans, but the fans would help cool the house faster, Porter said. The outdoors can pull the hot air from your home, leaving a cooler temperature or bringing in the breeze. Just be sure to close windows as the sun comes out, then open them when the weather is cool again.
You might not typically leave windows open for safety reasons, but if you're at home more anyway due to the pandemic, this method could be feasible, Porter said.
Just resting near a fan would reduce your body temperature as well.
Place box fans facing out of the windows of rooms you're spending time in to blow out hot air and replace it with cold air inside.
If the weather in your area tends to fall between 50 and 70 degrees Fahrenheit in the mornings and evenings, opening the windows on both sides of the house during those times can facilitate a cross-flow ventilation system. If you do this, you can opt to use or not use the fans, but the fans would help cool the house faster, Porter said. The outdoors can pull the hot air from your home, leaving a cooler temperature or bringing in the breeze. Just be sure to close windows as the sun comes out, then open them when the weather is cool again.
You might not typically leave windows open for safety reasons, but if you're at home more anyway due to the pandemic, this method could be feasible, Porter said.
Just resting near a fan would reduce your body temperature as well.
If you have windows that face the sun's direction in the morning through afternoon, close the curtains or blinds over them to "keep the sun from coming directly into the house and heating up (the) inside," Porter said.
You could also install blackout curtains to insulate the room and reduce temperature increases that would happen during the day.
If you do turn the air conditioning on, don't set it below 70 degrees Fahrenheit in an effort to cool the house faster, said Samantha Hall, managing director of Spaces Alive, an Australia-based design research company helping to create healthy, sustainable buildings.
"It just runs for longer to reach that temp and will keep going until you start to feel a bit chilly and is then hard to balance," she added. Instead, keep the unit temperature as high as possible while still comfortable.
If you have windows that face the sun's direction in the morning through afternoon, close the curtains or blinds over them to "keep the sun from coming directly into the house and heating up (the) inside," Porter said.
You could also install blackout curtains to insulate the room and reduce temperature increases that would happen during the day.
If you do turn the air conditioning on, don't set it below 70 degrees Fahrenheit in an effort to cool the house faster, said Samantha Hall, managing director of Spaces Alive, an Australia-based design research company helping to create healthy, sustainable buildings.
"It just runs for longer to reach that temp and will keep going until you start to feel a bit chilly and is then hard to balance," she added. Instead, keep the unit temperature as high as possible while still comfortable.
Cotton is one of the most breathable materials, so cotton sheets or blankets could help keep you cool through the night.
The lower the thread count of the cotton, the more breathable it is, Porter said. That's because higher thread counts have more weaving per square inch.
Cotton is one of the most breathable materials, so cotton sheets or blankets could help keep you cool through the night.
The lower the thread count of the cotton, the more breathable it is, Porter said. That's because higher thread counts have more weaving per square inch.
If you can't sleep through the night because you're too hot, try sleeping somewhere besides your bedroom, if that's an option. Heat rises, so if you have a lower or basement level in your home, set up a temporary sleeping area there to experience cooler temperatures at night.
If you can't sleep through the night because you're too hot, try sleeping somewhere besides your bedroom, if that's an option. Heat rises, so if you have a lower or basement level in your home, set up a temporary sleeping area there to experience cooler temperatures at night.
Common advice for staying cool without air conditioning includes refrigerating or freezing wet socks, blankets or clothing then ringing them out to wear while you sleep. But this isn't a good idea, Porter said.
Because of "the amount of energy they can absorb from your body that night, they will be warm in just a matter of minutes," he said. "And then you'd have damp stuff that would mold your mattress. So you definitely don't want to do that."
Common advice for staying cool without air conditioning includes refrigerating or freezing wet socks, blankets or clothing then ringing them out to wear while you sleep. But this isn't a good idea, Porter said.
Because of "the amount of energy they can absorb from your body that night, they will be warm in just a matter of minutes," he said. "And then you'd have damp stuff that would mold your mattress. So you definitely don't want to do that."
If no one's using a room that doesn't have vents or registers, close the door to that area to keep the cool air confined to only occupied areas of the house.
If no one's using a room that doesn't have vents or registers, close the door to that area to keep the cool air confined to only occupied areas of the house.
Incandescent light bulbs generate a higher temperature than LED light bulbs do. To make the switch, watch for sales on energy-efficient bulbs, then slowly replace the bulbs in your house, Porter said.
Switching light bulbs can save money but won't reduce a lot of heat in the home, Hall said. However, if you focus on switching the bulbs in areas you're sitting near, that would make a more noticeable difference, Porter said.
Shutterstock via CNN
Incandescent light bulbs generate a higher temperature than LED light bulbs do. To make the switch, watch for sales on energy-efficient bulbs, then slowly replace the bulbs in your house, Porter said.
Switching light bulbs can save money but won't reduce a lot of heat in the home, Hall said. However, if you focus on switching the bulbs in areas you're sitting near, that would make a more noticeable difference, Porter said.
Oven heat can spread throughout your house. Keep the heat centralized in one area, such as a slow cooker. Or, cook outdoors on a grill to keep the heat outside.
Oven heat can spread throughout your house. Keep the heat centralized in one area, such as a slow cooker. Or, cook outdoors on a grill to keep the heat outside.
Eating an ice pop or ice cream to cool down may help for a moment. But don't go overboard on the sugar if you're overheated or at risk of being overheated, Porter said.
"Sugar would run your metabolism up and you'd start feeling internally hot," he said. "So the cool treat might be good, but the extra sugar might not."
Eating an ice pop or ice cream to cool down may help for a moment. But don't go overboard on the sugar if you're overheated or at risk of being overheated, Porter said.
"Sugar would run your metabolism up and you'd start feeling internally hot," he said. "So the cool treat might be good, but the extra sugar might not."
If you've tried everything and still can't beat the heat at home, you could look online for any local programs that are offering ductless air conditioners.
Depending on your state, some cooling centers — air-conditioned public facilities where people might go for relief during extremely hot weather — may be open and taking precautions to ensure they're as safe as possible. You could start by checking with your local utility offices, as they would know who is offering certain programs, Porter recommended.
If you've tried everything and still can't beat the heat at home, you could look online for any local programs that are offering ductless air conditioners.
Depending on your state, some cooling centers — air-conditioned public facilities where people might go for relief during extremely hot weather — may be open and taking precautions to ensure they're as safe as possible. You could start by checking with your local utility offices, as they would know who is offering certain programs, Porter recommended.
The first day of summer 2022 brought soaring temperatures across a large part of the United States. National Weather Service
Heat domes involve high-pressure areas that trap and heat up the air below. NOAA
