a gravel road in Eureka Valley (which connects to a road running from Big Pine to the Grapevine section of Death Valley), the dunes became part of the Death Valley National Park as part of its expansion in 1994. Foot travel in the dunes is permitted, but vehicle access is prohibited. A primitive campground is located at the north end of the dune field. Sand dunes also exist in Death Valley near Stovepipe Wells. The Eureka Dunes share regional characteristics with the Kelso Dunes in the Mojave Desert. Morphology The Eureka Dunes are an example of a complex-linear dune – the main ridge is a static linear dune but there are active star dunes formations superimposed on the linear dune A linear dune has alternating slip faces on opposite sides of the crest. This means that both sides of the dune have similar slopes and wind must have come from both the northern and southern ends of the valley. Star dunes have "arms" radiating off of a central crest that change direction as the wind direction changes. Little is known about the past of the Eureka Dunes and its development. The sand source is unknown, although some scientists believed that it originated from an ancient lake at the northern end of the valley. Booming The unique booming characteristic of the Eureka Dunes is caused by the relative motion of moving sand grains. The sound has been compared to moans, hums, drums, and, in the case of Eureka, a distant propeller plane. Most researchers agree that the average sand grain size should be smaller than 300 μm, well-sorted with no dusty material, dry and in low humidity, loosely packed, and each sand grain should be spherical and smooth The booming sound occurs when a sheet of sand avalanches down the slip face, exciting the sand grains. The friction between these grains creates an acoustic air wave that emits an audible sound. Ecology The Eureka Dunes are the home of several unique (and protected) plant species. The Eureka Dune Grass (Swallenia alexandrae), the Eureka Evening Primrose (Oenothera californica eurekensis), and the Shining Locoweed (Astragalus lentiginosus micans) are only found in this area. Visitors to the dunes may also experience other unique aspects of these dunes, other than the booming. In wet weather, patterns can be seen in the sand that reveals the diverse sources, and the complex Aeolian process by which these