Death Valley is a desert located in the southwestern United States. It is the lowest, driest, and hottest location in North America. Badwater, a basin located within Death Valley, is the specific location of the lowest elevation in North America at 85.5 m (282 ft) below sea level. This point is only 76 miles (123 km) east of Mount Whitney, the highest point in the contiguous United States. Death Valley holds the record for the highest reliably reported temperature in the Western hemisphere, 134°F (56.7°C) at Furnace Creek in 1913—just short of the world record, which was 136°F (58°C) in El Azizia, Libya, on September 13, 1922.

Located on the border between California and Nevada, southeast of the Sierra Nevada mountains in the Great Basin and the Mojave Desert, Death Valley constitutes much of Death Valley National Park and is the principal feature of the Mojave and Colorado Deserts Biosphere Reserve. It is located mostly in Inyo County, California. It runs from north to south between the Amargosa Range on the east and the Panamint Range on the west; the Sylvania Mountains and the Owlshead Mountains form its northern and southern boundaries, respectively. It has an area of about 3,000 square miles (~7,800 km²). Death Valley shares many characteristics with other places around the world that lie below sea level.

Geography

Geologically, Death Valley is considered one of the best examples of the basin and range configuration. It lies at the southern end of a geological trough known as Walker Lane, which runs north into Oregon. The valley is bisected by a right lateral strike slip fault system, represented by the Death Valley Fault and the Furnace Creek Fault. The eastern end of the left lateral Garlock Fault intersects the Death Valley Fault. Furnace Creek and the Amargosa River flow through the valley but eventually disappear into the sands of the valley floor.

Death Valley also contains salt pans. According to current geological consensus, during the middle of the Pleistocene era there was a succession of inland seas (collectively referred to as Lake Manly) located where Death Valley is today. As the area turned to desert the water evaporated, leaving behind the abundance of evaporitic salts such as common sodium salts and borax, which were subsequently exploited during the modern history of the region, primarily 1883 to 1907.

As a general rule, lower altitudes tend to have higher temperatures because the sun heats the ground and that heat is then radiated upward, but as the air begins to rise it is trapped by the surrounding elevation and the weight of the air (essentially the atmospheric pressure) above it. The atmospheric pressure is higher at very low altitudes than it is under the same conditions at sea level because there is more air (more distance) between the ground and the top of the atmosphere. This pressure traps the heat near the ground, and also creates wind currents that circulate very hot air, thereby distributing the heat to all areas, regardless of shade and other factors.

This process is especially important in Death Valley because of its specific climate and geography. Because the atmosphere is so dry and the ground is largely flat and unobstructed by plants, a high percentage of the sun's heat is able to reach the ground and be absorbed by the soil and rocks. When the hot air begins to rise it is trapped not only by atmospheric pressure and gently rising elevation, but also by high mountain ranges on all sides, and the hot wind currents are also trapped by the mountains so that they stay mostly within the valley. Death Valley holds temperature records because it has an unusually high number of factors that lead to high atmospheric temperatures.

Climate

Temperatures in the Valley can range from highs around 130°F (54°C) in the summer to lows below 32°F (0°C) in the winter. The National Climatic Data Center reports that temperatures at Furnace Creek reach at least 90°F (32°C) on an average of 189.3 days annually and at least 100°F (38°C) on an average of 138.0 days annually. The highest average temperature is in July at 117°F (47°C), with temperatures of 122°F (50°C) or higher being very common. The highest temperature ever recorded in the United States, according to National Weather Service records, was 134°F (56.7°C) at Furnace Creek (then known as Greenland Ranch) during a sandstorm on July 10, 1913. Freezing temperatures, on the other hand, occur an average of 11.7 days each year. The lowest temperature on record at Furnace Creek Inn is 15°F (-9°C), but nighttime temperatures in summer may only fall to 85°F to 95°F (30°C to 35°C).

Parts of the valley receive less than 2 in (50 mm) of rain annually. At Furnace Creek Inn, average annual precipitation is 2.33 inches and an average of 18.1 days per year have measurable precipitation. The greatest monthly precipitation on record was 2.59 inches in January 1995; the one-day record is 1.47 inch of precipitation, which fell on April 15, 1988. The average evaporation rate in the bottom of Death Valley is 150 inches per year. In the winter, precipitation approaching Death Valley is usually released onto the slopes to its west, causing a rain shadow. The four major mountain ranges to the west of Death Valley contribute to this effect.

Although Death Valley gets very little rain, it is prone to flooding during heavy rains because the soil is unable to absorb the water quickly. The runoff can produce dangerous flash floods. In August 2004, such flooding caused two deaths and caused the national park to close. On rare occasions, light snow has fallen on the valley floor. The most recent snow flurries at Furnace Creek Inn were on January 5, 1974.

credited to wikipedia and flickr: realkuhl