Context

California’s Death Valley registered a temperature of 54.4 degrees Celsius or 129.9 degrees Fahrenheit on August 16, 2020, which, once verified, could be the hottest temperature ever recorded on Earth.

About

• Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert.
• The valleyis bounded on the west by the Panamint Range and on the east by the Black, Funeral, and Grapevine mountains of the Amargosa Range.
• It is one of the hottest places on Earth, along with deserts in the Middle East and the Sahara.
• As the hottest, driest and lowest national park, Death Valley is a land of extremes. 

Highlights

• The temperature was recorded at the United States National Weather Service’s automated weather station at Furnace Creek, near the border with Nevada, at 3:41 pm local time on the afternoon of August 16.
• The all-time highest temperature ever recorded is 134°F or 56.7°C on July 10, 1913, at the Greenland Ranch in the Death Valley.
• However, since the temperature-recording mechanisms a century ago were not as advanced, many have doubted if that reading was reliable.
• Similarly, a reading of 131°F or 55°C from July 1931 in Tunisia, has also been challenged.
• The temperature recorded at Furnace Creek has been termed as ‘preliminary’ and not ‘final’. Some have said that if it is verified as correct, it will be a new record.

Why Death Valley is so hot?

Death Valley’s crazy heats are caused by a combination of the lack of water, geography, and materials that make up the valley.

• Lack of water: The average yearly rainfall in Death Valley is only 2 inches. This is less than many other deserts in the world, averaging around 10 inches of rain annually. This intense lack of water also creates a lack of plants in the area resulting in the expanses of sand in the valley open to constant heating by the sun.
• Geography: The lower levels of mountain ranges create an interesting phenomenon of trapping the hot air within the valley. Sand and rocks make up the valley floor which radiate a large amount of heat. However, because of the geography, this hot air cannot escape. Instead, the hot air rises along the valley walls, cools slightly and then falls back to the valley floor to be heated even more by the hot sand and low elevation air pressure. 

This concept of movement by heating and cooling is called convection and exists in many other life circumstances like the boiling of water or in a kitchen oven.

What is ‘Heat Dome’?

• The high temperature recorded on August 16 is said to be a result of a so-called ‘heat dome’ that is smothering the west coast of the United States.
• The National Oceanic and Atmospheric Administration or NOAA describes it thus:
• High pressure circulation traps hot ocean air like a lid or a cap trapping heat at the surface and favouring the formation of a heat wave.
• To summarize, a heat dome is a pocket of hot air that is trapped in the upper atmosphere and refuses to move.
• While it stagnates there, it heats everything around it, forcing hot air down to the ground, where the air lingers.
• The combination of hot air and humidity will drive the heat index much higher, making the event doubly dangerous.
• Additionally, one of the most dangerous features is that the temperature may not reduce very much at night. This makes an endangered person more endangered, and results in even more deaths.