This is the famous Horizontal Falls in the Kimberley region of western Australia. Although called waterfalls, this natural phenomenon actually consists of immense tidal currents hurtling through narrow coastal gorges. When the tide turns, the water ‘falls’ back in the other direction. You can see here what they look like from one of the planes which conduct tours of the area. Incredible.

The Kimberley coast is one of the largest coastal wilderness areas in the world, and unusually (for such an empty area) seems to be very well covered by high-resolution imagery.

Thanks to woowoowoo for at least the 4 billionth time

Believe it or not, here’s something else to see in Antarctica! They are snow and ice dunes known as ’sastrugi’, and are formed on a snow surface by wind erosion and deposition. They differ from sand dunes in that the ridges are parallel to the prevailing winds.

These particular sastrugi are unusually large. NASAs Atmospheric Sciences Data Center says:

Usually sastrugi are only several centimeters high and several meters apart, but large portions of East Antarctica are covered by mega-sastrugi ice fields, with dune-like features as high as four meters separated by two to five kilometers. The mega sastrugi fields are a result of unusual snow accumulation and redistribution processes influenced by the prevailing winds and climate conditions. MISR imagery indicates that these mega sastrugi were stationary features between 2002 and 2004.

NASA has lots more information and a great image too, and although the pattern of dunes has changed, I believe you can still identify the exact region I’ve highlighted in our thumbnail. Cool.

Thanks to Twombly for letting us know what this was