Extreme heat appears to be killing people in America鈥檚 national parks at an alarming pace this year, highlighting both its severity and the changing calculus of personal risk in the country鈥檚 natural places as climate change fuels more weather extremes.Related video above: If you鈥檙e planning outdoor activities this summer, here鈥檚 how to stay safe in record-setting temperaturesMore people are suspected to have died since June 1 from heat-related causes in national parks than an average entire year, according to park service press releases and preliminary National Park Service data provided to CNN. No other year had five heat-related deaths by July 23, park mortality data that dates to 2007 shows, and the deadliest month for heat in parks 鈥� August 鈥� is yet to come.The deaths reported so far are still under investigation, but all five died in temperatures that hit 100 degrees, a searing microcosm of a much more widespread pattern of extreme heat that has broken more than 3,000 high-temperature records across the US since early June.That kind of heat has proven an indiscriminate killer in the nation鈥檚 parks: A 14-year-old boy died on a trail in southwest Texas鈥� Big Bend National Park in 119-degree heat, his 31-year-old father died seeking help to save him.A 65-year-or-older man died hiking on June 1 in Big Bend.A 57-year-old woman died hiking a trail in Arizona鈥檚 Grand Canyon National Park.A 71-year-old man collapsed and died outside a restroom in California鈥檚 Death Valley National Park after park rangers believe he hiked a nearby trail.A 65-year-old man was found dead in his disabled vehicle on the side of the road in Death Valley National Park, with park rangers suspecting he succumbed to heat illness while driving and then baked in temperatures as high as 126 degrees.Heat is the deadliest type of weather, killing on average more than twice as many people each year as hurricanes and tornadoes combined. But heat deaths are notoriously difficult to track in the US, with one 2020 study estimating that they were undercounted in some of the most populous counties.The National Park Service faces the same challenges and told CNN that the true toll of this year鈥檚 extreme heat and recent past heat may be even higher. They need to collect and corroborate death reports with hundreds of individual parks and the equally vast and complex web of local and state officials that medically determine the cause of death. As a result, some of the most recent death statistics from 2020 to 2023 could 鈥渃hange significantly,鈥� park spokespeople said. That鈥檚 already proven true. Two of this year鈥檚 five deaths happened after the park service provided the data to CNN in early July. Still, the current statistics offer a glimpse into the deadly potential of this unrelenting heat, especially in its epicenter: the Southwest.Ground zero for extreme heat deathsAll of this year鈥檚 suspected heat-related deaths took place in just three national parks: Grand Canyon, Death Valley and Big Bend. These three parks are also responsible for more than half of the 68 heat-related deaths reported by the park service since 2007. That鈥檚 no surprise 鈥� all three parks are located in the nation鈥檚 oven, the Southwest, and all but one of the deaths happened west of the Mississippi River. It鈥檚 normal for the Southwest to be hot. But the heat this year, especially the longevity of it, is far from normal. Phoenix, just a few hours south of the Grand Canyon, shattered its record for consecutive days at 110 degrees-plus and only dropped to 97 degrees overnight at times during the streak, a record-warm low temperature. A recent report from Climate Central, a non-profit research group, found that the Southwest heat wave in the first half of July was made at least five times more likely by human-caused climate change. Average annual temperatures across the Southwest increased by 1.6 degrees Fahrenheit between 1901 and 2016, according to the Fourth National Climate Assessment, the federal government鈥檚 periodic climate change report. The climate crisis has also worsened the region鈥檚 most severe drought in centuries, which created an ongoing crisis over water supplies from the river that etched the Grand Canyon into the earth. And projections show that temperatures will continue to rise to the tune of 8.6 degrees 鈥� resulting in 45 more days over 90 degrees each year for parts of the region by 2100 under the worst-case scenarios.The country鈥檚 national parks are ground zero for this warming. A 2018 study found that they had warmed twice as fast as the rest of the US from 1895 to 2010 due to human-caused climate change. National parks in the Southwest and in Alaska were the 鈥渕ost severely damaged by human-caused climate change鈥� and experienced the most pronounced warming, said Patrick Gonzalez, climate scientist at the University of California at Berkeley and the study鈥檚 author. But he also said that damage was happening 鈥渁ll across America and all across our national parks.鈥濃淐arbon pollution from cars, power plants and deforestation 鈥� human sources 鈥� has already damaged our national parks, and in years like this we see the potential acute damage, severe one-year damage,鈥� Gonzalez told CNN. Heat risk and damage to national parks will only increase if unabated carbon pollution continues, Gonzalez said. That鈥檚 changing the personal risk calculus for summer recreation now and in the future in increasingly hotter national parks.The deadliest activity you can do in heatThe 300 million-plus people who visit the parks each year are already encountering warmer temperatures and are at a greater risk for heat illness as a result. Park visitation also peaks during the summer, furthering that risk.The park service doesn鈥檛 universally keep track of heat-related illnesses that don鈥檛 result in death, but multiple park representatives said the number of heat illnesses was much greater than heat mortality. Multiple medical responses a week that are 鈥減robably heat-related鈥� happen during the summer at Death Valley National Park, park spokesperson Abby Wines told CNN. Grand Canyon National Park doesn鈥檛 track heat-specific illness, but carries out hundreds of rescues and so-called 鈥渉iker assists鈥� for less-severe issues most commonly because of 鈥渓ack of physical conditioning,鈥� park spokesperson Joelle Baird told CNN. Baird said they see a spike in ranger responses to heat-related illnesses when temperatures reach 95 degrees on trails at the midway point between the top and the bottom of the canyon.Extreme heat can trigger heat illness in as little as 20 to 30 minutes for people doing anything strenuous outdoors, like hiking, because heat acts as a 鈥減erfect storm,鈥� which overloads the body until it eventually short-circuits and shuts down, Dr. Matthew Levy, a professor at Johns Hopkins University School of Medicine, told CNN. Hiking was the most common cause of heat-related death in the national parks data, representing more than 60% of all deaths. Park spokespeople said that typically, less-experienced hikers find themselves in compromising situations by overestimating their abilities or under-preparing for the heat, but heat illness and death can and have happened in experienced hikers, too. Maggie Peikon is a self-proclaimed 鈥渁vid hiker鈥� who has climbed some of the country鈥檚 highest mountains and even scaled an active volcano in Indonesia. She said part of the allure of hiking for experienced hikers is to 鈥渃hallenge my will.鈥� But even so, she said, hiking in this kind of heat isn鈥檛 worth it. 鈥淢ost of the challenges I鈥檝e pushed myself to do, there鈥檚 a level of enjoyment there, and it just feels like a punishment to go out when it鈥檚 that hot,鈥� said Peikon, who works as the manager of communications at the American Hiking Society.鈥淚 think I鈥檝e just learned what I鈥檓 capable of, and that鈥檚 not just from a physical standpoint, hiking is very mental as well,鈥� Peikon told CNN. 鈥淭hat was something that has stuck with me on every single hike that I do, especially the challenging ones: What you鈥檙e capable of is entirely up to you.鈥� Too hot to rescuePersonal responsibility weighs heavily in the policy direction the individual national parks take when dealing with the heat. Parks proactively message visitors about the heat online and in signage posted at the trails that warn of the dangerous and 鈥渢ragic鈥� consequences of high temperatures. Death Valley posts bright red 鈥淪TOP Extreme Heat Danger鈥� signs at low-elevation trailheads, which urge people to stay off trails after 10 a.m. and to hike only at high elevations, where temperatures are lowest. 鈥淧eople are responsible for their own safety,鈥� Death Valley spokesperson Abby Wines told CNN. 鈥淲e try to get information out to people so they鈥檙e aware, but one of the problems with heat, I think, is that often people think it鈥檚 a matter of being tough enough. They think 鈥榦h, I might be uncomfortable, but that鈥檚 all and I can push through it.鈥� But heat is deadly.鈥滻t鈥檚 so hot in Death Valley that the park warns visitors that it can鈥檛 and won鈥檛 rescue people.鈥淲e don鈥檛 want to put our own staff at risk of heat fatality by doing a physical carry out in extreme heat conditions,鈥� Wines said, adding that the medical helicopter can鈥檛 get enough lift to take off because temperatures are so hot. That was the case in the most recent death in Death Valley on July 19 when the temperature was 117 degrees, a park release notes. What parks seem to rarely do is close trails because of the heat. The park representatives CNN spoke to said there is no national policy or guidance to close if temperatures reach a certain level. Trails do close because of other kinds of extreme weather, including winter storms and tropical systems. Park officials said those decisions are made at the individual park level based on the hazards there and that it was technically possible individual parks could choose to close trails or limit access if the heat got too extreme. Trails in Lake Mead National Recreational area in Arizona and Nevada do close seasonally because of the heat, and Grand Canyon National Park has at least entertained the idea to close trails. 鈥淚t is something that I鈥檝e heard come up every single year, this time of year, so I don鈥檛 think it鈥檚 beyond the National Park Service or Grand Canyon,鈥� Baird, Grand Canyon National Park鈥檚 spokesperson, told CNN. 鈥淚 think the thought and stance has always been to push out more hiker education to try to change and influence people鈥檚 behavior rather than having a reactionary decision to close trails, because people can hike successfully. We just have to provide enough information and tools for them to be successful.鈥滸rand Canyon is the deadliest park for extreme heat with 16 deaths since 2007, the preliminary data from the National Park Service would suggest, a toll Baird said would be 鈥渕uch higher鈥� if the park didn鈥檛 also have one of the most robust and proactive responses to heat. Grand Canyon pioneered a Preventative Search and Rescue team after a particularly dangerous and taxing year for rescue teams in 1996. The teams are medically trained and meet hikers at the start of trails to make sure they are adequately prepared for the journey, provide assistance with water or snacks and even contact and check in with hikers once they鈥檙e on the trails. This preventative approach has decreased the number of expensive, 鈥渓ast resort鈥� search and rescues that are typically done via helicopter. But despite these efforts, there are still between 300 and 350 search and rescues each year at Grand Canyon and there have been 172 so far this year, with around 70 coming since Memorial Day.鈥淕rand Canyon is an amazing place, everyone should hike into the canyon if they have the ability to do so,鈥� Baird said. 鈥淗owever, this time of year is not optimal.鈥� Park officials and hiking experts recommended checking the weather and park alerts before going out on the trail, to get acclimated to heat before your trip and know your personal limits, to shorten activities outdoors, carry more water than you think you might need, find shadier trails, tour the park by air-conditioned car or even just skip the hike altogether to reduce the chance that heat continues to turn deadly.鈥淚t鈥檚 not worth the risk of experiencing heat illness because of the outcomes,鈥� Andrea Walton, Southeast Region Public Affairs Specialist for the park service, told CNN. 鈥淎t minimum you鈥檙e going to feel really bad the next day鈥� or worse, 鈥減otentially ending up in the hospital, or worst case, experiencing a fatal incident.鈥�
Extreme heat appears to be killing people in America鈥檚 national parks at an alarming pace this year, highlighting both its severity and the changing calculus of personal risk in the country鈥檚 natural places as climate change fuels more weather extremes.
Related video above: If you鈥檙e planning outdoor activities this summer, here鈥檚 how to stay safe in record-setting temperatures
More people are suspected to have died since June 1 from heat-related causes in national parks than an average entire year, according to park service press releases and preliminary National Park Service data provided to CNN. No other year had five heat-related deaths by July 23, park mortality data that dates to 2007 shows, and the deadliest month for heat in parks 鈥� August 鈥� is yet to come.
The deaths reported so far are still under investigation, but all five died in temperatures that hit 100 degrees, a searing microcosm of a much more widespread pattern of extreme heat that has broken more than 3,000 high-temperature records across the US since early June.
That kind of heat has proven an indiscriminate killer in the nation鈥檚 parks:
- A 14-year-old boy in southwest Texas鈥� Big Bend National Park in 119-degree heat, his 31-year-old father died seeking help to save him.
- A 65-year-or-older man died hiking on June 1 in Big Bend.
- A 57-year-old woman in Arizona鈥檚 Grand Canyon National Park.
- A 71-year-old man in California鈥檚 Death Valley National Park after park rangers believe he hiked a nearby trail.
- A 65-year-old man was found on the side of the road in Death Valley National Park, with park rangers suspecting he succumbed to heat illness while driving and then baked in temperatures as high as 126 degrees.
Heat is , killing on average more than twice as many people each year as hurricanes and tornadoes combined. But heat deaths are , with one estimating that they were undercounted in some of the most populous counties.
The National Park Service faces the same challenges and told CNN that the true toll of this year鈥檚 extreme heat and recent past heat may be even higher. They need to collect and corroborate death reports with hundreds of individual parks and the equally vast and complex web of local and state officials that medically determine the cause of death.
As a result, some of the most recent death statistics from 2020 to 2023 could 鈥渃hange significantly,鈥� park spokespeople said.
That鈥檚 already proven true. Two of this year鈥檚 five deaths happened after the park service provided the data to CNN in early July. Still, the current statistics offer a glimpse into the deadly potential of this unrelenting heat, especially in its epicenter: the Southwest.
Ground zero for extreme heat deaths
All of this year鈥檚 suspected heat-related deaths took place in just three national parks: Grand Canyon, Death Valley and Big Bend. These three parks are also responsible for more than half of the 68 heat-related deaths reported by the park service since 2007.
That鈥檚 no surprise 鈥� all three parks are located in the nation鈥檚 oven, the Southwest, and all but one of the deaths happened west of the Mississippi River.
It鈥檚 normal for the Southwest to be hot. But the heat this year, especially the longevity of it, is far from normal. Phoenix, just a few hours south of the Grand Canyon, shattered its record for consecutive days at 110 degrees-plus and only dropped to 97 degrees overnight at times during the streak, a record-warm low temperature.
A recent report from Climate Central, a non-profit research group, found that the Southwest heat wave in the first half of July was made at least by human-caused climate change.
Average annual temperatures across the Southwest between 1901 and 2016, according to the Fourth National Climate Assessment, the federal government鈥檚 periodic climate change report. The climate crisis has also worsened the region鈥檚 most severe drought in centuries, which created an ongoing crisis over water supplies from the river that etched the Grand Canyon into the earth. And projections show that temperatures will continue to rise to the tune of 8.6 degrees 鈥� resulting in 45 more days over 90 degrees each year for parts of the region by 2100 under the worst-case scenarios.
The country鈥檚 national parks are ground zero for this warming. A 2018 study they had warmed twice as fast as the rest of the US from 1895 to 2010 due to human-caused climate change.
National parks in the Southwest and in Alaska were the 鈥渕ost severely damaged by human-caused climate change鈥� and experienced the most pronounced warming, said Patrick Gonzalez, climate scientist at the University of California at Berkeley and the study鈥檚 author. But he also said that damage was happening 鈥渁ll across America and all across our national parks.鈥�
鈥淐arbon pollution from cars, power plants and deforestation 鈥� human sources 鈥� has already damaged our national parks, and in years like this we see the potential acute damage, severe one-year damage,鈥� Gonzalez told CNN.
Heat risk and damage to national parks will only increase if unabated carbon pollution continues, Gonzalez said. That鈥檚 changing the personal risk calculus for summer recreation now and in the future in increasingly hotter national parks.
The deadliest activity you can do in heat
The 300 million-plus people who visit the parks each year are already encountering warmer temperatures and are at a greater risk for heat illness as a result. Park visitation also peaks during the summer, furthering that risk.
The park service doesn鈥檛 universally keep track of heat-related illnesses that don鈥檛 result in death, but multiple park representatives said the number of heat illnesses was much greater than heat mortality. Multiple medical responses a week that are 鈥減robably heat-related鈥� happen during the summer at Death Valley National Park, park spokesperson Abby Wines told CNN.
Grand Canyon National Park doesn鈥檛 track heat-specific illness, but carries out hundreds of rescues and so-called 鈥渉iker assists鈥� for less-severe issues most commonly because of 鈥渓ack of physical conditioning,鈥� park spokesperson Joelle Baird told CNN.
Baird said they see a spike in ranger responses to heat-related illnesses when temperatures reach 95 degrees on trails at the midway point between the top and the bottom of the canyon.
Extreme heat can trigger heat illness in as little as 20 to 30 minutes for people doing anything strenuous outdoors, like hiking, because heat acts as a 鈥減erfect storm,鈥� which overloads the body until it eventually short-circuits and shuts down, Dr. Matthew Levy, a professor at Johns Hopkins University School of Medicine, told CNN.
Hiking was the most common cause of heat-related death in the national parks data, representing more than 60% of all deaths. Park spokespeople said that typically, less-experienced hikers find themselves in compromising situations by overestimating their abilities or under-preparing for the heat, but heat illness and death can and have happened in experienced hikers, too.
Maggie Peikon is a self-proclaimed 鈥渁vid hiker鈥� who has climbed some of the country鈥檚 highest mountains and even scaled an active volcano in Indonesia.
She said part of the allure of hiking for experienced hikers is to 鈥渃hallenge my will.鈥� But even so, she said, hiking in this kind of heat isn鈥檛 worth it.
鈥淢ost of the challenges I鈥檝e pushed myself to do, there鈥檚 a level of enjoyment there, and it just feels like a punishment to go out when it鈥檚 that hot,鈥� said Peikon, who works as the manager of communications at the American Hiking Society.
鈥淚 think I鈥檝e just learned what I鈥檓 capable of, and that鈥檚 not just from a physical standpoint, hiking is very mental as well,鈥� Peikon told CNN. 鈥淭hat was something that has stuck with me on every single hike that I do, especially the challenging ones: What you鈥檙e capable of is entirely up to you.鈥�
Too hot to rescue
Personal responsibility weighs heavily in the policy direction the individual national parks take when dealing with the heat.
Parks and in signage posted at the trails that warn of the dangerous and 鈥渢ragic鈥� consequences of high temperatures. Death Valley posts bright red 鈥� at low-elevation trailheads, which urge people to stay off trails after 10 a.m. and to hike only at high elevations, where temperatures are lowest.
鈥淧eople are responsible for their own safety,鈥� Death Valley spokesperson Abby Wines told CNN. 鈥淲e try to get information out to people so they鈥檙e aware, but one of the problems with heat, I think, is that often people think it鈥檚 a matter of being tough enough. They think 鈥榦h, I might be uncomfortable, but that鈥檚 all and I can push through it.鈥� But heat is deadly.鈥�
It鈥檚 so hot in Death Valley that the park warns visitors that it can鈥檛 and won鈥檛 rescue people.
鈥淲e don鈥檛 want to put our own staff at risk of heat fatality by doing a physical carry out in extreme heat conditions,鈥� Wines said, adding that the medical helicopter can鈥檛 get enough lift to take off because temperatures are so hot.
That was the case on July 19 when the temperature was 117 degrees, a park release notes.
What parks seem to rarely do is close trails because of the heat. The park representatives CNN spoke to said there is no national policy or guidance to close if temperatures reach a certain level.
Trails do close because of other kinds of extreme weather, and tropical systems. Park officials said those decisions are made at the individual park level based on the hazards there and that it was technically possible individual parks could choose to close trails or limit access if the heat got too extreme.
Trails in Lake Mead National Recreational area in Arizona and Nevada because of the heat, and Grand Canyon National Park has at least entertained the idea to close trails.
鈥淚t is something that I鈥檝e heard come up every single year, this time of year, so I don鈥檛 think it鈥檚 beyond the National Park Service or Grand Canyon,鈥� Baird, Grand Canyon National Park鈥檚 spokesperson, told CNN. 鈥淚 think the thought and stance has always been to push out more hiker education to try to change and influence people鈥檚 behavior rather than having a reactionary decision to close trails, because people can hike successfully. We just have to provide enough information and tools for them to be successful.鈥�
Grand Canyon is the deadliest park for extreme heat with 16 deaths since 2007, the preliminary data from the National Park Service would suggest, a toll Baird said would be 鈥渕uch higher鈥� if the park didn鈥檛 also have one of the most robust and proactive responses to heat.
Grand Canyon pioneered a Preventative Search and Rescue team after a particularly.
The teams are medically trained and meet hikers at the start of trails to make sure they are adequately prepared for the journey, provide assistance with water or snacks and even contact and check in with hikers once they鈥檙e on the trails.
This preventative approach has decreased the number of expensive, 鈥渓ast resort鈥� search and rescues that are typically done via helicopter. But despite these efforts, there are still between 300 and 350 search and rescues each year at Grand Canyon and there have been 172 so far this year, with around 70 coming since Memorial Day.
鈥淕rand Canyon is an amazing place, everyone should hike into the canyon if they have the ability to do so,鈥� Baird said. 鈥淗owever, this time of year is not optimal.鈥�
Park officials and hiking experts recommended checking the weather and park alerts before going out on the trail, to get acclimated to heat before your trip and know your personal limits, to shorten activities outdoors, carry more water than you think you might need, find shadier trails, tour the park by air-conditioned car or even just skip the hike altogether to reduce the chance that heat continues to turn deadly.
鈥淚t鈥檚 not worth the risk of experiencing heat illness because of the outcomes,鈥� Andrea Walton, Southeast Region Public Affairs Specialist for the park service, told CNN. 鈥淎t minimum you鈥檙e going to feel really bad the next day鈥� or worse, 鈥減otentially ending up in the hospital, or worst case, experiencing a fatal incident.鈥�
