Ice Ice Baby

Another cool shot from NASA's Earth Observatory:


The image has 6MB worth of detail so you can really zoom in! This is a shot of the Sea of Okhotsk (which is between Siberia and Kamchatka for all the Risk players in the room). Cold arctic outbreaks, like those that put the Canadian prairies in deep freeze from time to time, cause intense cooling sessions over this sea. When the ice - which must be almost 100% pure fresh water for it to keep its crystalline form - removes fresh water from the sea, the enhanced saltiness of the water left behind is actually enough to cause that water to sink. This heavy water will sink to the bottom of the sea, and then cascade down into the deep ocean, like a slow motion water-fall. (Interestingly the same thing happens in the Mediterranean Sea because evaporation removes water but leaves salt behind.)

A neat feature of the image is that you don't really see clouds until the wind (which is blowing offshore) gets past the ice and starts blowing over the water.