Mojave River Valley Museum
Joshua Tree National Park -
Joshua Tree Guide
The desert is immense and infinitely variable, yet delicate and and fragile.
It is a land shaped by sudden torrents of rain and climatic extremes.
Rainfall is sparse and unpredictable. Streambeds are usually dry and
are few. This land may appear lifeless, but within its parched
intricate living systems,
each fragment depending on the whole system for survival.
Joshua Tree National Park is located in southern California on the eastern end of the broad
mountainous belt called the Transverse Ranges, which stretch from Point Arguello, 50 miles
west of Santa Barbara, eastward for nearly 300 miles to the Eagle Mountains in the Mojave
Desert. Unlike most mountain ranges in North America that run north-south, the Transverse
Ranges lie on an east-west axis.
The area of southeastern California is a rain shadow desert. The rain shadow effect
is produced by the high mountains on the west, which block the movement of wet winter
storms. Coastal storms moving east collide with Mount San Jacinto (10,804 ft.) and
Mount San Gorgonio (11,502 ft.) dropping most of their moisture on the west sides
of these mountains. Land on the east side receives much less rain, which results in
a desert environment.
During late August or September occasional tropical storms move into southern California
from the south. These storms end up on the east side of the Peninsular Ranges and can
dump a considerable amount of water in a short time. Some five to 10 inches of rain may
fall in a few hours, representing a large portion of Joshua Tree’s annual precipitation.
White Tank Natural Arch area slideshow