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Death Valley had planet’s hottest 24 hours on record Sunday amid punishing heat wave

Its temperature, averaged over day and night, was an unprecedented 118.1 degrees

With the Amargosa Mountain Range in the background at sunrise, a sign warns park visitors of “extreme heat danger” along California's Highway 190 on Sunday. (Melina Mara/The Washington Post)

When dawn broke Sunday in Death Valley, Calif., the low temperature was a sweltering 107.7 degrees, the highest ever recorded in North America. By the late afternoon, the mercury had swelled to a blazing 128.6 degrees. The combination of the two produced the highest daily average temperature ever observed on the planet: 118.1 degrees.

The astonishingly hot temperatures occurred amid a punishing heat wave in the West, focused between interior Oregon, Central Valley in California and southern Nevada. Intensified by human-caused climate change, the heat wave is fueling fast-moving wildfires and only slowly abating.

Sunday’s probable world record daily average temperature was registered at the Stovepipe Wells weather station in the northern part of Death Valley National Park. It is separate from the more frequently referenced temperature measurements at Death Valley’s Furnace Creek, about 18 miles to the southeast. Furnace Creek is home to the highest maximum temperature recorded on the planet: 134 degrees, set July 10, 1913.

Amid dangerous heat wave, Death Valley closes in on record-high temperatures

Sunday morning’s low of 107.7 degrees at Stovepipe Wells marked the second highest minimum temperature observed worldwide, only trailing the coastal city of Quriyat, Oman, which never dropped below 108.7 degrees on June 26, 2018.

The afternoon high that day in Stovepipe Wells of 128.6 was its highest on record (since 2004). It was actually hotter in Furnace Creek on Friday and Saturday, where the temperature soared to 130 and 129.4 degrees, but somewhat lower minimum temperatures resulted in less searing averages compared with Stovepipe Wells. (Low temperatures at Furnace Creek on Friday and Saturday were 104 and 99 compared with Stovepipe Wells’s 108 on Sunday.)

News of Sunday’s record-setting average temperature at Stovepipe Wells was first posted on Twitter by Thierry Goose, who monitors internal weather data from Canada, and corroborated by both Maximiliano Herrera, an expert on world weather extremes, and Etienne Kapikian, a forecaster with Meteo France.

While any significant record-setting temperatures in Death Valley since Friday are preliminary and require validation from the World Meteorological Organization, the measurements at Stovepipe Wells are probably legitimate as they were produced from the U.S. Climate Reference Network, considered the gold standard for weather observation. The network relies on high quality instruments that monitor weather in stable, undisturbed locations, according to the National Oceanic Atmospheric Administration. Temperatures are computed based on the output of three independent thermometers.

Historic heat in Death Valley began Friday

The record-setting 24 hours in Stovepipe Wells on Sunday capped a blistering three-day stretch in Death Valley, which began with the 130-degree high at Furnace Creek on Friday. It equaled the 130-degree mark set in August in the same location and, if confirmed, would mark the planet’s highest temperature since at least 1931.

Only two other known measurements have been higher: (1)The 134-degree reading from Furnace Creek in 1913, and (2) a 131-degree reading from Kebili, Tunisia, set July 7, 1931.

Death Valley soars to 130 degrees, matching Earth’s highest temperature in at least 90 years

But Christopher Burt, an expert on world weather extremes, questions the legitimacy of both of those measurements. He called the 1913 Furnace Creek reading “essentially not possible from a meteorological perspective” and wrote that the 1931 Tunisia reading has “serious credibility issues.”

In other words, the 130-degree readings set at Furnace Creek both Friday and last year, if validated, may be the highest pair of reliably measured temperatures observed on Earth.

Even if you accept the 1913 high temperature, the daily average temperatures this year and last year are hotter because of much higher minimum temperatures. On Friday, when the high was 130, the low was 104. But in 1913, when the high was reportedly 134, the low was a much milder 85.

The exceptionally high temperatures in Furnace Creek have also been notable for their longevity. They reached 126 on Wednesday and Thursday, before peaking at 130 on Friday. On Saturday and Sunday, they climbed to 129.4 and 127.9. Monday’s forecast again calls for highs to reach the high 120s. The low hasn’t fallen below 99 degrees since Tuesday.

Record heat throughout the West

Since late last week, historically significant heat has roasted surrounding locations as far west as western Colorado and as far north as Northern California, including:

  • Grand Junction, Colo., which reached an all-time high of 107 degrees on Friday.
  • Las Vegas, which tied its record of 117 on Saturday.
  • St. George, Utah, which reached 117 degrees on Saturday, preliminarily tying the state’s temperature record.
  • Desert Rock, Nev., and Barstow-Daggett, Calif., which matched their all-time highs of 113 and 118 on Saturday, respectively.
  • Bishop, Calif., which set an all-time high of 111 on Saturday, surpassing the previous mark of 110.
  • Downtown Sacramento, which posted its second-highest temperature recorded, reaching 113 degrees Saturday, just one off its all-time high of 114. California’s capital city hit at least 110 for a record-tying third straight day.

Heat fuels wildfires, relief coming in some areas

The hot and exceptionally dry weather has created tinderbox conditions for the rapid spread of wildfires. According to the National Interagency Fire Center, 59 large blazes are burning in a dozen states, 11 of them in California and Oregon. Smoke from wildfires in the West and British Columbia spread over “most of the western half of the U.S.,” according to the National Weather Service.

As of early Monday, the Bootleg Fire in southwest Oregon had burned more than 153,000 acres, the blaze doubling in size daily between Friday and Sunday.

Bootleg Fire rages through Oregon, threatening California’s electricity supply

The fire had made electricity transmission into California unreliable, and the state’s grid operator urged consumers to conserve energy on Monday.

Temperatures on Monday and Tuesday will remain above normal in the Southwest and California’s Central Valley but will back off gradually from record-setting territory.

Toward the middle of the week, the heat dome, or zone of high pressure responsible for the sweltering temperatures, is forecast to weaken while the summer monsoon strengthens. This will bring some much-needed rain in Arizona, New Mexico, Nevada and western Colorado, all of which are enduring extreme to exceptional drought conditions.

However, long-range computer models show potential for another intense heat wave in the West building by next weekend, focused on the central and northern Rockies, which could bring more exceptionally high temperatures.

The science of heat domes and how drought and climate change make them worse

The heat wave afflicting the West is the third in just over three weeks, after the “unprecedented” Pacific Northwest event at the end of June and a record-setting blast in the Southwest in the middle of the month; together, they vaulted the nation to its hottest June on record. The heat wave in the Pacific Northwest was made at least 150 times as likely by human-caused climate change, according to a panel of scientists.

More on heat waves

Our warming climate: It’s not just you ⁠— summers in the U.S. are getting hotter, and experts say heat waves will likely become even more frequent and intense. Take a look at what extreme heat does to the human body.

How to stay safe: It’s better to prepare for extreme heat before you’re in it. Here’s our guide to bracing for a heat wave, tips for staying cool even if you don’t have air conditioning, and what to know about animal safety during extreme heat. Traveling during a heat wave isn’t ideal, but here’s what to do if you are.

Understanding the science: Sprawling zones of high pressure called heat domes fuel heat waves. Here’s how they work. You can also read more about the link between weather disasters and climate change, and how leaders in the U.S. and Europe are responding to heat.

Tell the Post: What questions do you have about extreme heat, wildfires, droughts or other climate-related topics?