Almost all of the 46 centimeters (18 inches) of rain that falls in Etosha National Park each year arrives between October and March. The influx of moisture—a boon for the wildlife—completely transforms the landscape. It greens parched grasslands, replenishes ephemeral streams and watering holes, and sometimes pools enough to cover a flat basin with a layer of water that extends for thousands of square kilometers.
When the rains slow and then cease during the dry season (April through September), any water in the basin slowly evaporates, depositing salt and other minerals on the land surface in the process. Over time, this cycle of flooding and evaporation has built up a mineral-encrusted surface called a salt pan. In fact, the striking white surface of the salt pan is what originally earned Etosha Pan its name. In the language of the local Ovambo people, etosha means "great white place."
In the series of false-color images above, the bright salt pan offers a clear contrast with the parched (brown) landscapes that surround it in the dry season and the lush (green) landscapes of the wet season. All three images use a combination of infrared and visible light to increase the contrast between water and land. Water varies in color from electric blue to navy, with darker shades indicating deeper water. Living vegetation, even sparse vegetation, appears green. Orange areas are burn scars from recent fires. All of the false-color images above were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite.
Notice that a few new burn scars are visible in the August 2020 image. They were likely intentionally set management fires, which help reduce the likelihood of more destructive fires breaking out later. Satellite imagery shows that the scar closest to the Ekuma River burned for a few days beginning on July 13, 2020.
Though unusually dry weather left Etosha Pan without water in December 2019, just two months later a surge of rain had refilled much of it. By late August 2020, the salt pan had mostly dried again, aside from some water near the mouth of the Ekuma River.
Etosha National Park supports large populations of elephants, lions, rhinos, and several other animals. The dry season is one of the best times for visitors to see animals because they often congregate around shrinking bodies of water.
NASA Earth Observatory images by Lauren Dauphin, using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview. Story by Adam Voiland.