The Reasons Behind Death Valley's Extremes

Why Furnace Creek is the Hottest and Driest Place in North America

Jun 16, 2009

Death Valley has a sinister ring to it, but what are the reasons for its status as one of the most inhospitable places on earth?

Death Valley holds three records. It is the hottest, the driest and the lowest place in the North American continent. With names for localities such as Furnace Creek, Badwater Basin, Stovepipe Wells, Devil’s Golf Course and Dante’s Peak, one knows that to visit this place in the height of summer means an encounter with monstrous conditions. But the reasons behind these climatic extremes can be found within Death Valley’s unique surrounding topography.

Why Death Valley is Hot and Dry

Death Valley is a 156-mile (251-kilometre) long trough between the mountain ranges of Amargosa to the East and the Panamint to the West. The Panamint Range rises to over 11,000 feet (3,353 metres) above America’s lowest point, Badwater Basin 282 feet (85.5 metres) below sea level. Badwater Basin is a huge saltpan, 40 miles (64 kilometres) long and 5 miles (8 kilometres) wide. But this basin is no ordinary basin, for its unusual lowness is combined with a saltwater spring that constantly bubbles to the surface, so creating the saltpan. This blindingly white environment has the effect of reflecting the heat of the sun onto the surrounding rocks where the energy is stored and slowly released creating conditions like a clay oven. Because there is little vegetation around to offer shade or to temper the sun's heat, much of the sun's radiation is able to reach the valley bottom.

Furthermore, the clear dry air cannot escape this huge basin. It has no choice but to be heated by the land where it rises before being recycled back to the ground to be reheated. These descending pockets of air are only slightly cooler than the surrounding air before being heated further by compression at ground level. This superheated air often blows through the valley, searing anything in its path.

What is a Rain Shadow?

When air is forced over mountains, it condenses into rain and cloud. This is known as the “windward” side of the mountain. Once the air has passed over, this drier air descends to the bottom and is warmed by compression. This dry, warm area is known as a “rain shadow” and occurs on the lee side of mountains.

The Indian Monsoons are a large scale example of a rain shadow. The conditions occur when a low-pressure system fed by summer heat forms over the Asian continent and pulls the air in from the Indian Ocean towards the Tibetan Plateau. As this warm moist air rises to higher ground, it condenses and brings the monsoon rains. The wrung dry air over the other side of the mountains bring dry weather. This is where the rain shadow occurs.

Famous examples of winds generated by the rain shadow effect are the Chinook in the Rockies and the Foehn in the Alps. But in the case of Death Valley, the air has been wrung out by four mountain ranges including the Sierra Nevada and the Panamint mountains creating four rain shadow effects. The resultant air is exceptionally hot and dry.

Badwater Basin and Furnace Creek

Furnace Creek is the present record holder for the hottest temperatures ever known in North America. Located at a central point in the valley, measurements have been collated from weather instruments there since the turn of the last century. However, new instruments have been set up in the 1990s by the NASA Ames Research Centre (ARC) at Badwater Basin, 20 miles (32 kilometres) south of Furnace Creek. Overlooked by Dante’s Peak, Badwater is in a slightly more sheltered position where the heat from the sun and the glare from the saltpans are reflected onto the rocks nearby. For this reason, there is scepticism regarding the placement of the instruments at Badwater.

Death Valley’s Topography

Death Valley’s extreme heat and dryness are due to its unusual topography, being located in a deep basin at the foot of high mountains. Extra-dry air wrung out by four rain shadows becomes trapped within the basin where is it heated and reheated by the land. The white saltpans at Badwater create further heat by reflecting the sun's rays onto nearby rocks where the energy is released like a storage heater. There is no vegetation to temper the sun's heat. The superheated air is allowed to blow through the valley unadulterated in a searing wind. With such unique conditions, it is no wonder that Death Valley is renowned throughout the world.

Useful Links and References

William J Burroughs et al., Weather, The Ultimate Guide to the Elements, HarperCollins, 1996

The copyright of the article The Reasons Behind Death Valley's Extremes in Climatology is owned by Rachel Wills. Permission to republish The Reasons Behind Death Valley's Extremes in print or online must be granted by the author in writing.