The Racetrack Playa, or The Racetrack, is a scenic dry lake feature with "sailing stones" that inscribe linear "racetrack" imprints. It is located above the northwestern side of Death Valley, in Death Valley National Park, Inyo County, California, U.S.
Geography
The Racetrack Playa is approximately 3 miles long and 1.2 miles wide and is located at a height of 3708 feet in a north–south valley east of the Panamint Range within Death Valley National Park. It receives only 3 inches of annual precipitation and is bounded on all sides by north–south ranges rising 1500 to 2000 feet. The overall drainage area is around 70 square miles, with most of it flowing onto the playa from eastern mountain rivers.
Rocks weighing up to 320 kg travel across Racetrack Playa in northern Death Valley National Park, California, leaving tracks. This phenomenon, which has been documented since 1948, is not unique and has been observed in various playas in southern California, the Tunisian Sahara, and South Africa.
A thorough system was put up for the investigation of Racetrack Playa's rock movement, including a weather station near the playa, time-lapse cameras centered on the southeast corner, and 15 GPS-equipped boulders on the surface. The researchers went to the location for maintenance and data retrieval 5-8 times per year. From November to March each year, the time-lapse camera recorded hourly conditions.
Interwoof GPS loggers were installed in limestone blocks northeast of natural stones and captured GPS and temperature data every 60 minutes. They began recording constantly at one-second intervals after being triggered. draining into the playa, forming a shallow, short-lived endorheic lake. Under the hot desert sun, the thin veneer of water quickly evaporates leaving behind a surface layer of soft slick mud. As the mud dries, it shrinks and cracks into a mosaic pattern of interlocking polygons.
The shape of the shallow hydrocarbon lake Ontario Lacus on Saturn's moon Titan has been compared to that of Racetrack Playa.
Features
Racetrack is dry for almost the entire year and has no vegetation. When dry, its surface is covered with small but firm hexagonal mud crack polygons that are typically in diameter and about an inch (2.5 cm) thick. The polygons form in sets of three mud cracks at 120° to each other. A few days after a precipitation event, small mud curls, otherwise known as "corn flakes," form on the playa surface. Absence of these indicates that wind or another object has scraped away the tiny mud curls.
thumb|Sailing stone in Racetrack Playa
During the bimodal rainy season (summer and especially winter) a shallow cover of water deposits a thin layer of fine mud on and between the polygons of Racetrack. Heavier winter precipitation temporarily erases them until spring when the dry conditions cause new mud cracks to form in the place of the old cracks. Sandblasting wind continually helps to round the edges of exposed polygons. Annual precipitation is and ice cover can be thick. Typically only part of the playa will flood in any given year.
The Racetrack was vandalised in late 2016.
A portion of the playa's shoreline indicates ice activity, notably on the east side of the southernmost arm. A pavement of angular rock fragments and periodic alignments of bigger stones reveal little ice ramparts. Stone traces and ridges near the shore suggest ice thrusting and shearing. start to melt during periods of light wind. These thin floating ice panels create an ice shove that moves the rocks at up to five meters (16') per minute.
Islands
thumb|right|300px|[[The Grandstand in the northwest area of the playa]]
Two islands of bedrock outcrops rise dramatically above the playa's surface at its northern end. The larger landmark is The Grandstand, a high dark quartz monzonite outcrop, rising in dramatic contrast from the bright white surface of the Racetrack. The second "island" feature is a smaller carbonate outcrop.
Springs
thumb|Depressions in the Racetrack playa are intermittent springs that are active at time of precipitation. Detailed view illustrate conical holes where the water comes out on the surface when this area receive excess of precipitation.
There are three areas of aligned depressions (intermittent springs) in the playa.
Spinal Springs is in the central part of the Racetrack playa. It is long and starts, at its northern end, with conical depressions only a few centimeters (inches) deep. Traced southward the depressions increase to ~ in width with scattered creosote shrubs. They then narrow and become shallower again, and finally disappear. Further north and south along this linear formation, there were several other depressions that may be a continuation of the Spinal Springs alignment.