Formed from volcanic ash, these crescent-shaped dunes are a rare phenomenon, and are technically referred to as barkan. These dunes are formed when there’s ample dust on the ground and a unidirectional wind to create the moving effect.

Abstract: Sand can create an endlessly moving collection of dunes, drifted by the prevailing winds. However, it can happen that, changing the winds, also the motion and the shape of the dunes change. Moreover, in the case that wind is blowing from a prevailing direction, the dunes migrate.

The big, shallow fiords and estuaries were filled with sand, deposited during sea-level changes. This sand, dating back to the Glacial and late Glacial times, is the origin of today’s beaches along Jæren. Human activities tore away the vegetation cover, exposing soil to the wind and thereby reinforcing sand drift.

These are the barchan, transverse, blowout, linear, and composite dunes. Although it is sometimes easier to see different dune types from the air, some deserts have only one predominant type.

What factors determine the shape of sand dunes? A sand dunes form depends on the wind direction and speed, the amount of sand available, and the amount of vegetation.

40 feet a year

There are several factors that determine the shape of sand dunes. These include wind speed and direction, the type and amount of sand occurring in an…

A dune is a mound of sand formed by the wind, usually along the beach or in a desert. Every dune has a windward side and a slipface. Examples of dunes are – longitudinal dunes. Narrow elongated dunes that form when the wind blows in two convergent directions.

A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. Subaqueous dunes can form from the action of water flow (fluvial processes) on sand or gravel beds of rivers, estuaries, and the sea-bed.

: a hill or ridge of sand piled up by the wind.

Badain Jaran Desert Dunes: Inner Mongolia, China The desert’s dunes are the highest stationary sand dunes in the world (the highest reaching 1,600 feet) and emit a constant rumbling and booming that sounds, strangely enough, like singing.

Here are a few of the world’s best dunes:

• Huacachina, Peru.
• Badain Jaran Dunes, Mongolia/China.
• White Sands National Monument, New Mexico.
• Simpson Desert, Australia.
• Little Sahara Recreation Area, Utah.
• Great Dune of Pyla, France.

Colorado

7 Incredible Sand Dunes to Explore Around the U.S.

• Oregon Sand Dunes National Recreation Area.
• Dumont Dunes, California.
• Great Sand Dunes National Park, Colorado.
• White Sands National Monument, New Mexico.
• Mesquite Flat Sand Dunes, Death Valley.
• Algodones Dunes, California.
• The Outer Banks, North Carolina/Virginia.

* While Florida leads in most beach sand replenishment measures, California has placed the most sand by volume on its beaches – 394 million cubic yards of sand since its first project in the Los Angeles coastal suburb of San Pedro in 1927.

Star Dune

Always plan your dunes time for early morning or evening to avoid burning sand, high winds, or thunderstorms with lightning. The Medano Pass Primitive Road usually opens by late May.

Giant dunes can reach widths of between a few hundred metres and a few kilometres, and can take the shape of ridges, crescents or stars. Deserts also have small dunes, typically tens of metres wide, which are formed when sand grains blown by the wind are shaped into regular patterns.

Sand collapse: Digging deep holes anywhere in the sand can be dangerous, thanks to sand’s potential to collapse. Wind and sand: Remember, the dunes are where they are because of the wind! Wind-blown sand can be painful and dangerous.

“An amount as small as a grain of sand can kill you,” Dr Karen Grimsrud, Alberta’s chief medical officer, told reporters after traces of carfentanil were found in the bodies of two men who had overdosed. “Carfentanil is about 100 times more toxic than fentanyl and about 10,000 times more toxic than morphine.”

Wear closed-toe shoes when hiking on the sand. Take sunscreen, as skin burns easily at this high elevation (8,200 feet/2,499m at the visitor center). Remember your pet’s feet are sensitive to burns, too. Avoid hiking on the dunes mid-day in summer when the sun is shining.

Walking on dunes can destroy the plants that hold them together. Without these plants, wind would erode the sand off the dune, diminishing its effectiveness as a natural barrier. This is why it is so important to stay off the dunes and always use designated dune walkways.

By walking or playing on sand dunes, we damage the beach grass and other plants that hold the dune together. It takes only a few footsteps to damage the extensive root system of beach grass, and when that happens, the plant can no longer hold sand in place. Over time, the dune and all its benefits will be lost.

Human impacts Around the world coastal dunes are eroding and under pressure due to increased sediment loss because of increased coastal human activities. Loss in vegetation cover exposes sand to the action of wind and leaves sand dunes vulnerable to increased erosion as it is vegetation that binds sand together.

Dunes can be stabilized using indegenous grasses and other plants which help by “reducing the velocity of waves and absorbing their energy” (Measures for Stabilizing Coastal Dunes, USDA). These plants take root and begin to form a strong, thick barrier which anchors the sand dune and helps keep sand in place.