A dangerous and persistent heat wave swept through much of the south-central and western United States on Thursday, bringing near-record temperatures and increasing the risk of wildfires across a large swath of the country.
The National Weather Service said that as of Thursday afternoon, more than 113 million Americans were under some form of heat warning. The advisories, which include extreme heat advisories and heat advisories, extended about 2,000 miles from Oregon to Louisiana.
Locations including Phoenix and Las Vegas, which were under extreme heat warnings, could both challenge all-time record highs over the next few days, as temperatures rise above 110 degrees, AccuWeather said.
“Unfortunately, the long-term forecast over the weekend and into next week is for an increasingly significant and oppressive heatwave,” the Met Office said.
Meanwhile, as the United States endures extreme heat, the planet as a whole experienced its warmest June on record, climate scientists said Thursday.
Around the world, scientists say the unusually warm temperatures for this time of year, even in Antarctica where it is winter, are another example of climate change, made worse by fossil fuel emissions.
Heat can be dangerous and deadly
Experts warn that extreme heat and blazing sunshine can cause people to quickly become dehydrated. People are urged to avoid strenuous activities during daylight hours, increase their fluid intake and seek an air-conditioned environment when possible to avoid the possibility of heat exhaustion and heat stroke, AccuWeather warned.
“Please plan accordingly, this is not a good time to be hiking or staying outside for long periods,” Weather Service The Los Angeles office said on Twitter. “If you need to work outside, change your work hours to early morning, take frequent breaks and drink water!”
Extreme heat is the deadliest weather-related event in the United States. It kills more people than hurricanes or tornadoes – combined.
Federal agencies report that about 700 Americans die each year from extreme heat, but some studies estimate that number may be closer to 1,300 deaths annually. Another study found that up to 20,000 deaths may have been related to extreme heat from 2008 to 2017.
Snow accumulation remains dangerous in California
Amidst the focus on the dangers of heat. Rivers swollen by melting snowpack in the Sierra Nevada last winter are still dangerous, noted Daniel Swain, a climate scientist at the University of California, Los Angeles.
“There is still snow to melt at the highest elevations, and it will actually start to melt very quickly…during this heat wave,” Swain said during a news conference.
“Be aware that the water will still be ice cold despite the air temperature, and it can flow very quickly, much faster than normal in mid-July,” he said.
The National Oceanic and Atmospheric Administration (NOAA) and NASA say June was the world's hottest on record.
June 2023 also marks the 47th consecutive June and the 532nd consecutive month with temperatures above the 20th century average, NOAA reported.
Additionally, the National Oceanic and Atmospheric Administration (NOAA) said the first half of 2023 was the third-warmest year on record, with the global temperature reaching 1.82 degrees above the 20th century average. There is now a 97% chance that 2023 will be one of the five hottest years on record.
The European Copernicus Climate Change Service and Berkeley Earth also said June was the hottest on record.
Scientists say the warmth the planet is enduring this year is due to a combination of human-caused global warming and a strengthening El Niño climate pattern in the Pacific Ocean.
“The onset of El Niño has implications for placing 2023 on the list of hottest years on record when combined with a backdrop of climate warming,” Marshall Shepherd, a professor of meteorology at the University of Georgia, said last month.
The El Niño phenomenon is expected to continue during the winter
Speaking of El Niño: The famous weather pattern is expected to continue through the upcoming winter of 2023-2024, according to US federal forecasters. The Climate Prediction Center announced Thursday. Specifically, there is more than a 90% chance that El Niño will continue through the winter, according to the Chinese Communist Party.
Meteorologists also said El Niño should be of moderate to strong intensity, and added that there was a one in five chance it would become “historically strong,” rivaling the winter of 1997-1998 or 2015-2016.
Florida is also under heat warnings
Before sunrise Thursday, the heat index on Virginia Key in Miami reached 99.3 degrees, dawning another hot day in an extended heat wave blanketing South Florida.
As of Thursday, Miami had set an unofficial record of 33 days with a heat index above 100 degrees, breaking the record set in 2020, according to Brian McNoldy, a senior research associate at UCLA's Rosenstiel School of Marine, Atmospheric and Earth Sciences. University of Miami. The unofficial record comes from the historical records of a weather station located on the south side of Miami International Airport since 1948.
Ten Florida counties are under an advisory for heat index readings above 100 degrees on Thursday, according to the National Weather Service. The heat index – what the air temperature looks like – comes from a combination of air temperature and dew point temperature.
The oceans are hot, hot, hot
Sea surface temperatures in South Florida have risen as much as 5 degrees above 1991-2020 averages, the hottest during this time of year since at least 1985, according to NOAA.
The ocean heatwave is among a series of extreme marine heatwaves hitting more than 40% of the world's oceans. Global sea surface temperatures reached a record high for this time of year in May and June, the World Meteorological Organization said this week. Heat waves are expected to expand to 50% by September.
Michael Sparrow, head of the World Meteorological Organization's Global Climate Research Department, said ocean temperatures in the North Atlantic were “far higher than anything predicted by models.”
The Copernicus Climate Change Service reports that heat in the Atlantic Ocean is caused by a combination of short-term circulation in the atmosphere and long-term changes in the ocean.
The World Meteorological Organization said: “It is not believed to be related to the El Niño phenomenon, which has just begun to spread in the tropical Pacific region, and is expected to affect temperatures later in the year and until 2024.”
The World Meteorological Organization said higher than normal ocean temperatures could affect coral reefs, fish, ocean circulation and weather. Coral reef scientists and marine biologists are very concerned about the impact on coral reefs and other marine life.
If high temperatures continue through the summer, “coral reefs will undergo bleaching,” Derek Manzello, NOAA's coral reef monitoring coordinator, said this week. Bleached coral is starving to death because it has lost its main source of nutrition – the algae that feed on it. They live symbiotically within their tissues.
“If the heat stress doesn’t subside, the coral will die,” Manzello said. “Corals can recover from bleaching if heat stress subsides,” he said, but even when they do, they may suffer poor growth and reproduction and be more susceptible to disease.
Cerberus heat wave hits Europe
An intense heat wave dubbed “Cerberus” is sweeping most of Europe this week, and is expected to intensify in the coming days.
Temperatures in parts of Mediterranean Europe are expected to reach 113 degrees as of Friday.
The high-pressure system affecting the region, which crossed the Mediterranean from North Africa, has been named Cerberus after the three-headed dog in ancient Greek mythology that guarded the gates to the underworld.
Meteorologists said that the heat wave will also be felt in parts of northern Europe.
“Italy, Spain, France, Germany and Poland are facing an intense heatwave, with temperatures expected to rise to 48 degrees Celsius (118 degrees Fahrenheit) on the islands of Sicily and Sardinia – the highest temperatures ever recorded in Europe,” the European Space Agency said Thursday.
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Death Valley can reach 130 degrees
California's famous “Death Valley” region, home to the world's highest ever temperature and one of the hottest places on Earth, could reach 130 degrees over the weekend, meteorologists said. The world record air temperature of 134 degrees was recorded in Death Valley on July 10, 1913, at the Furnace Creek lookout site, AccuWeather said.
Wildfire fears are on the rise
Meanwhile, California's wildfire season is heating up amid hot, dry conditions with a series of fires burning across the state this week, said Secretary Wade Crowfoot of the California Natural Resources Agency.
“As we get deeper into summer and the vegetation that grew during the wet spring dries up, we are seeing an uptick in wildfire activity,” Crowfoot said Wednesday during a government news conference.
'A clear signal of climate change'
Sure, it's summer and it's supposed to be hot. But experts say the intensity and duration of this heat wave in cities like Phoenix is being exacerbated by human-caused climate change. “Of course we expect hot summers (in Arizona), but part of what we're seeing with climate change is longer, more intense heat waves,” said Kathy Jacobs, who directs the Center for Climate Adaptation Science and Solutions at the University of Arizona.
However, the intensity and duration of the current heatwave “is not what we would expect in the absence of climate change. There is a clear signal of climate change here, but you can't say what proportion is directly attributable to climate change,” Jacobs said.
Contributing: Adriana Rodriquez, USA TODAY; Brandon Loomis, Arizona Republic; Associated Press
