This weather event has killed more Americans on average than hurricanes
By
Adriana Navarro, AccuWeather staff writer
Updated Jul 2, 2021 7:54 PM EDT
On average, extreme heat events have killed more people in the United States on average from 1991 to 2020 than any other weather event. (Data via National Weather Service)
Despite the destruction wrought by tropical systems, the reach claimed by floods and the moment's notice given by tornadoes, heat events have notoriously claimed more lives on average than any other weather event over the past 30 years.
Extreme heat has contributed to an average of 138 fatalities every year over the past 30 years (1991-2020), according to data from the National Weather Service. Following as the weather event with the second highest fatalities on average within the same time frame is flooding, then tornadoes, hurricanes, lightning, winter storms and then extreme cold weather events.
However, even this high number may not portray the full scale of the danger that heat can present. Reviewing past extreme heat events have revealed challenges in capturing the full scale of fatalities from the events, according to the United States Environment Protection Agency. The example the agency gave was from the Chicago heat wave of 1995, which is estimated to have claimed over 700 lives rather than the 400-some fatalities reported from the heat.
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Here's a look at a few factors that have been contributing to the deadliness of extreme heat events over the decades:
A heat dome develops from a large poleward shift in the jet stream, which in turn becomes distorted and essentially traps a high pressure system in place.
This high pressure traps air over an area, causing it to sink, and as the air from higher elevations -- with lower pressure -- falls to the surface, the increase in pressure heats up the air significantly, AccuWeather Meteorologist Max Gawryla explained.
Gregory Matarazzo takes a break from cycling as the temperatures hovered over 100 degrees in Missoula, Montana, on Wednesday, June 30, 2021. (AP Photo/Tommy Martino)
"It's effectively the same physical principles your pressure cooker uses to heat food, just on a much, much larger scale," Gawryla said.
While the big factors are the strength of that high and that it remains stationary, the topography of an area can also come into play.
"If you add in topography, it can help to trap the hot air and enhance the downward motion of the air," Gawryla explained. "For example, if you have winds which blow down the slope of a mountain, they will become notably hotter as they fall in elevation."
This is essentially what occurred during the heat wave that baked the Pacific Northwest during late June of 2021.
In the case of the Northwest, which had been subjected to a heat dome caused by a notably strong region of high pressure over the area, the mountains also prevented the air from spreading out.
He added that with that said, a heat dome can just as easily set up over any portion of the U.S., regardless of the terrain.
To date, the Northwest Pacific heat wave from Washington to Oregon has claimed the lives of dozens, and over 400 reports of "sudden and unexpected deaths" have been reported in British Columbia in Canada.
As sunlight rains down over a city, it's not just potted plants and sparse squares of grass that soak up the sun.
During mid-July of 1995, over 700 people in Chicago were estimated to have died from a blistering heat wave that hit the city. Temperatures had "only" reached up to 104 degrees at the peak of the hot weather, but the humidity and lack of wind made temperatures feel like they were around 120 degrees Fahrenheit and the "urban heat island" effect kept temperatures from dropping at night.
Workers at the Cook County morgue in Chicago wheel a body to refrigerator trucks on Tuesday, July 18, 1995. Several trucks were parked near the morgue to handle an overflow of bodies, most believed to be victims of the heat wave. (AP Photo/Mike Fisher)
"It seems obvious, but concrete can heat much more quickly than soil or plants in direct sunlight," Gawryla said. "When exposed to the sun, much more of the solar radiation is absorbed. This energy is then released in conductive heat, warming the air around it."
The result is the urban heat island effect, which Gawryla says can make conditions in a city even hotter and more dangerous than the nearby, less-widely paved areas.
Smaller micro heat islands can also form within a city depending on how tree cover and pavement are placed throughout the grid.
A study published in 2020 examined 108 cities nationwide and found that formerly redlined neighborhoods in nearly every one of the cities were hotter than the non-redlined neighborhoods. Vivek Shandas, a professor of urban studies and planning at Portland State University who co-authored the study, told NPR that the heat patterns seen in the study were likely the result of more concrete and fewer trees and green spaces in these hot spots.
This means that historically underserved populations who live in these neighborhoods -- even decades after the practice of redlining was outlawed -- are disproportionately impacted by heat events.
While the study found that, regionally, Midwest cities displayed the least differences in temperatures across the redlined and non-redlined neighborhoods compared to the Southeast and Western cities, it concluded that "historical housing policies may, in fact, be directly responsible for disproportionate exposure to current heat events."
During the Heat wave of 1995, mortality rates of the black community were roughly 1.5 times higher than those of their white counterparts, according to the Encyclopedia of Chicago. Most of the deaths were reportedly concentrated in the predominantly black communities on the South and West Sides of Chicago.
AccWeather RealFeel® Temperature aims to measure when the temperature "feels like" rather than simply what a thermometer reads.
To arrive at this measurement, the AccWeather RealFeel® Temperature takes into account the humidity, cloud cover, wind, sun intensity and the angle of the sun, which could potentially cumulate into an extreme difference.
For example, temperatures reached up to 104 degrees during the 1995 Chicago heat wave, AccuWeather meteorologists estimate that the weather conditions boosted the AccWeather RealFeel® Temperature to around 120 degrees Fahrenheit.
During a heat wave across the southeastern U.S. in 1983, Fayetteville, North Carolina, recorded a high of 109 on July 24, but the AccuWeather RealFeel® would have reached as high as 115 degrees.
That same day, Charleston, South Carolina, recorded a high of 101, but the AccuWeather RealFeel® would have been at 114 degrees. Savannah, Georgia, saw a smaller difference between the two, though not insignificant. While the temperature reached 103 degrees, it felt like 110.
While unusually hot days and heat waves are a natural part of the weather, days are growing warmer and heat waves more frequent and intense as Earth's climate warms, according to the Climate Science Special Report Executive Summary, overseen by the U.S. Global Change Research Program (USGCRP).
A report by the USGCRP on heat waves found that from the 1960s through the 2010s, not only are heat waves across major U.S. cities more frequent across the nation, but the length of the heat wave season is also lasting longer.
FILE - In this Tuesday, June 15, 2021, file photo, a pedestrian holds a bottle of cold water at a Salvation Army hydration station during a heatwave as temperatures hit 115-degrees in Phoenix. The Southwest U.S. continued to bake Saturday, June 19, and weather forecasters kept warnings in effect for excessive heat in Arizona, Nevada, and desert areas, at least through the weekend. (AP Photo/Ross D. Franklin, File)
The average number of heat waves that occur in major cities across the U.S. have more than tripled over the decades, from an average of two per year during the 1960s to more than six per year during the 2010s, according to data from the USGCRP.
Of the 50 major cities the USGCRP observed in the report, 46 experienced a "statistically significant" increase in the frequency of heat waves across the decades. The length of the heat wave season, measured as the number of days between the first heat wave of the year and the last, increased as well, noted as significant in 44 of the cities.
This Friday, Sept. 18, 2020, satellite image made available by the National Oceanic and Atmospheric Administration shows gray smoke from wildfires in the western United States drifting across the continent and the remnants of Hurricane Sally in the southeast. In the past week, swaths of the country have been burning and flooding in devastating extreme weather disasters. (NOAA via AP)
As the climate changes, people can expect to see even more extremes in the weather in the future, including heat events, according to AccuWeather Senior Meteorologist and Climate Expert Brett Anderson.
"People should expect to see even more extremes in the future. Extreme heat waves, floods and droughts that are considered rare today, will likely be more common," Anderson said. "For example, a 1- in 100-year event in the past may become more like a 1 in 10 or 1- in 5-year event in the near future."
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
Report a Typo
News / Weather News
This weather event has killed more Americans on average than hurricanes
By Adriana Navarro, AccuWeather staff writer
Updated Jul 2, 2021 7:54 PM EDT
On average, extreme heat events have killed more people in the United States on average from 1991 to 2020 than any other weather event. (Data via National Weather Service)
Despite the destruction wrought by tropical systems, the reach claimed by floods and the moment's notice given by tornadoes, heat events have notoriously claimed more lives on average than any other weather event over the past 30 years.
Extreme heat has contributed to an average of 138 fatalities every year over the past 30 years (1991-2020), according to data from the National Weather Service. Following as the weather event with the second highest fatalities on average within the same time frame is flooding, then tornadoes, hurricanes, lightning, winter storms and then extreme cold weather events.
However, even this high number may not portray the full scale of the danger that heat can present. Reviewing past extreme heat events have revealed challenges in capturing the full scale of fatalities from the events, according to the United States Environment Protection Agency. The example the agency gave was from the Chicago heat wave of 1995, which is estimated to have claimed over 700 lives rather than the 400-some fatalities reported from the heat.
CLICK HERE FOR THE FREE ACCUWEATHER APP
Here's a look at a few factors that have been contributing to the deadliness of extreme heat events over the decades:
Heat domes
A heat dome develops from a large poleward shift in the jet stream, which in turn becomes distorted and essentially traps a high pressure system in place.
This high pressure traps air over an area, causing it to sink, and as the air from higher elevations -- with lower pressure -- falls to the surface, the increase in pressure heats up the air significantly, AccuWeather Meteorologist Max Gawryla explained.
Gregory Matarazzo takes a break from cycling as the temperatures hovered over 100 degrees in Missoula, Montana, on Wednesday, June 30, 2021. (AP Photo/Tommy Martino)
"It's effectively the same physical principles your pressure cooker uses to heat food, just on a much, much larger scale," Gawryla said.
While the big factors are the strength of that high and that it remains stationary, the topography of an area can also come into play.
"If you add in topography, it can help to trap the hot air and enhance the downward motion of the air," Gawryla explained. "For example, if you have winds which blow down the slope of a mountain, they will become notably hotter as they fall in elevation."
This is essentially what occurred during the heat wave that baked the Pacific Northwest during late June of 2021.
In the case of the Northwest, which had been subjected to a heat dome caused by a notably strong region of high pressure over the area, the mountains also prevented the air from spreading out.
He added that with that said, a heat dome can just as easily set up over any portion of the U.S., regardless of the terrain.
To date, the Northwest Pacific heat wave from Washington to Oregon has claimed the lives of dozens, and over 400 reports of "sudden and unexpected deaths" have been reported in British Columbia in Canada.
"Urban heat island" effect
As sunlight rains down over a city, it's not just potted plants and sparse squares of grass that soak up the sun.
During mid-July of 1995, over 700 people in Chicago were estimated to have died from a blistering heat wave that hit the city. Temperatures had "only" reached up to 104 degrees at the peak of the hot weather, but the humidity and lack of wind made temperatures feel like they were around 120 degrees Fahrenheit and the "urban heat island" effect kept temperatures from dropping at night.
Workers at the Cook County morgue in Chicago wheel a body to refrigerator trucks on Tuesday, July 18, 1995. Several trucks were parked near the morgue to handle an overflow of bodies, most believed to be victims of the heat wave. (AP Photo/Mike Fisher)
"It seems obvious, but concrete can heat much more quickly than soil or plants in direct sunlight," Gawryla said. "When exposed to the sun, much more of the solar radiation is absorbed. This energy is then released in conductive heat, warming the air around it."
The result is the urban heat island effect, which Gawryla says can make conditions in a city even hotter and more dangerous than the nearby, less-widely paved areas.
Smaller micro heat islands can also form within a city depending on how tree cover and pavement are placed throughout the grid.
A study published in 2020 examined 108 cities nationwide and found that formerly redlined neighborhoods in nearly every one of the cities were hotter than the non-redlined neighborhoods. Vivek Shandas, a professor of urban studies and planning at Portland State University who co-authored the study, told NPR that the heat patterns seen in the study were likely the result of more concrete and fewer trees and green spaces in these hot spots.
This means that historically underserved populations who live in these neighborhoods -- even decades after the practice of redlining was outlawed -- are disproportionately impacted by heat events.
While the study found that, regionally, Midwest cities displayed the least differences in temperatures across the redlined and non-redlined neighborhoods compared to the Southeast and Western cities, it concluded that "historical housing policies may, in fact, be directly responsible for disproportionate exposure to current heat events."
During the Heat wave of 1995, mortality rates of the black community were roughly 1.5 times higher than those of their white counterparts, according to the Encyclopedia of Chicago. Most of the deaths were reportedly concentrated in the predominantly black communities on the South and West Sides of Chicago.
AccuWeather RealFeel® Temperature
AccWeather RealFeel® Temperature aims to measure when the temperature "feels like" rather than simply what a thermometer reads.
To arrive at this measurement, the AccWeather RealFeel® Temperature takes into account the humidity, cloud cover, wind, sun intensity and the angle of the sun, which could potentially cumulate into an extreme difference.
For example, temperatures reached up to 104 degrees during the 1995 Chicago heat wave, AccuWeather meteorologists estimate that the weather conditions boosted the AccWeather RealFeel® Temperature to around 120 degrees Fahrenheit.
During a heat wave across the southeastern U.S. in 1983, Fayetteville, North Carolina, recorded a high of 109 on July 24, but the AccuWeather RealFeel® would have reached as high as 115 degrees.
That same day, Charleston, South Carolina, recorded a high of 101, but the AccuWeather RealFeel® would have been at 114 degrees. Savannah, Georgia, saw a smaller difference between the two, though not insignificant. While the temperature reached 103 degrees, it felt like 110.
The impacts of climate change
While unusually hot days and heat waves are a natural part of the weather, days are growing warmer and heat waves more frequent and intense as Earth's climate warms, according to the Climate Science Special Report Executive Summary, overseen by the U.S. Global Change Research Program (USGCRP).
A report by the USGCRP on heat waves found that from the 1960s through the 2010s, not only are heat waves across major U.S. cities more frequent across the nation, but the length of the heat wave season is also lasting longer.
FILE - In this Tuesday, June 15, 2021, file photo, a pedestrian holds a bottle of cold water at a Salvation Army hydration station during a heatwave as temperatures hit 115-degrees in Phoenix. The Southwest U.S. continued to bake Saturday, June 19, and weather forecasters kept warnings in effect for excessive heat in Arizona, Nevada, and desert areas, at least through the weekend. (AP Photo/Ross D. Franklin, File)
The average number of heat waves that occur in major cities across the U.S. have more than tripled over the decades, from an average of two per year during the 1960s to more than six per year during the 2010s, according to data from the USGCRP.
Of the 50 major cities the USGCRP observed in the report, 46 experienced a "statistically significant" increase in the frequency of heat waves across the decades. The length of the heat wave season, measured as the number of days between the first heat wave of the year and the last, increased as well, noted as significant in 44 of the cities.
This Friday, Sept. 18, 2020, satellite image made available by the National Oceanic and Atmospheric Administration shows gray smoke from wildfires in the western United States drifting across the continent and the remnants of Hurricane Sally in the southeast. In the past week, swaths of the country have been burning and flooding in devastating extreme weather disasters. (NOAA via AP)
As the climate changes, people can expect to see even more extremes in the weather in the future, including heat events, according to AccuWeather Senior Meteorologist and Climate Expert Brett Anderson.
"People should expect to see even more extremes in the future. Extreme heat waves, floods and droughts that are considered rare today, will likely be more common," Anderson said. "For example, a 1- in 100-year event in the past may become more like a 1 in 10 or 1- in 5-year event in the near future."
Related:
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
Report a Typo