Chapter 2 - Physical Features

Chapter 2 Physical Features

The Joshua tree are a good indicator of The Mojave Desert’s boundaries. The Mountasins which surround this desert are the Tehachapi, San Gabrial and San Bernardino. In the North is the Great Shrub Basin and the Sonoran Desert to the south and East. The Colorado River borders the east and the Mojave river is a great source of water for the south
The Mojave Desert receives less than 10 inches (250 mm) of rain a year and is generally between 3,000 and 6,000 feet (1,000 and 2,000 m) in elevation. The Mojave Desert also contains the Mojave National Preserve, as well as the lowest and hottest place in North America: Death Valley, where the temperature normally approaches 120°F (49°C) in late July and early August. Zion National Park, in Utah, lies at the junction of the Mojave, the Great Basin, and the Colorado Plateau. Despite its aridity, the Mojave has long been a center of alfalfa production, fed by irrigation coming from groundwater and (in the 20th century) from the California Aqueduct.
The Mojave is a desert of temperature extremes and four distinct seasons. Winter months bring temperatures dipping to below 20 °F (-7 °C) on valley floors, and below 0 °F (-18 °C) at higher elevations. Storms moving from the Pacific Northwest can bring rain and snow across the region — more often, the rain shadow created by the Sierra Nevada as well as mountain ranges within the desert such as the Spring Mountains bring only clouds and wind. In longer periods between storm systems, winter temperatures in valleys can approach 80 °F (27 °C).
Spring weather continues to be influenced by Pacific storms, but rainfall is more widespread and occurs less frequently after April. By early June, it is rare for another Pacific storm to have a significant impact on the region's weather, and temperatures after mid-May are normally above 90 °F (32 °C) and frequently above 100 °F (38 °C).
Summer weather is dominated by heat — temperatures on valley floors can soar above 120 °F (49 °C) and above 130 °F (54 °C) at the lowest elevations — and the presence of the North American monsoon. Low humidity, high temperatures and low pressure draw in moisture from the Gulf of Mexico, creating thunderstorms across the desert southwest. While the Mojave does not get nearly the amount of rainfall that the Sonoran desert to the east receives, monsoonal moisture will create thunderstorms as far west as California's Central Valley from mid-June through early September.
Autumns are generally pleasant, with one to two Pacific storm systems creating regional rain events. October is one of the driest and sunniest months in the Mojave, and temperatures usually remain between 70 °F (21 °C) and 90 °F (32 °C) on the valley floors.
After temperature, wind is the most significant weather phenomenon in the Mojave. Across the region, windy days are common, and in areas near the transition between the Mojave and the California low valleys, including near Cajon Pass, Soledad Canyon and the Tehachapi areas. During the June Gloom, cooler air can be pushed out into the desert from Southern California; in Santa Ana wind events, hot air from the desert blows out into the Los Angeles basin and other coastal areas. Wind farms in these areas generate power from these winds.
The other major weather factor in the region is elevation. The highest peak within the Mojave is Charleston Peak at 11,918 feet (3,633 m), while Badwater in Death Valley is 282 feet (86 m) below sea level. Accordingly, temperatures and precipitation ranges wildly, in all seasons, across the region
http://en.wikipedia.org/wiki/Mojave_Desert