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Sailing StonesThe method by which these stones travel is still an unsolved mystery. At a place called The Racetrack Playa in Death Valley, there's a dry lake bed that is surprisingly flat, with only a 4cm height differential between the north and south ends. The high mountains surrounding the Racetrack are made mostly of dark dolomite and tower over the lake bed. When the heavy desert rains come, water pours down these mountains and onto the lake bed, forming a very shallow lake. Due to the hot temperatures of the region (because, you know, Death Valley), the water evaporates, leaving behind a layer of soft, very slick mud. There is a theory that high winds move the rocks at this time, the thin layer of mud acting as a lubricated surface. However, the fact that some stones move and others do not, or that some will simply change direction... makes the wind theory slightly suspect.
These rocks seem to only move every 2 or 3 years, and some tracks develop over 4 years. There have been research teams on the Playa since the 70s, but no one has yet to witness the stones actually moving.
Update: In 2014, a team of scientists and engineers were finally able to capture on video how it happens.
Water SpoutA water spout is technically a non-supercell tornado over water... and while it's usually weaker than its land-brother the tornado, stronger ones are possible.
Usually found in the tropics, they've been known to form over lakes as well. There are generally three types: non-tornadic, tornadic and snowspout. The first, non-tornadic (or fair weather waterspouts) are the most common and tend to live only about 20 minutes. A tornadic spout is much stronger, and basically an actual tornado over water. These, like tornados, are connected with severe thunderstorms. Finally, the snowspout (also known as a snow devil) is the rarest of the three types. Only six known pictures exist (four from Ontario, CA), and they require extremely cold temps over a body of warm water with a difference of a specific 34 degrees to form at all.
Ball LightningBall lightning is an unexplained atmospheric electrical phenomenon that refers to a luminous, usually spherical object (and it's not a piece o' the car) which can vary from pea-sized to several meters in diameter. It is usually associated with thunderstorms, but lasts considerably longer than the split-second flash of a lightning bolt.
Laboratory experiments have produced effects that are visually similar to reports of ball lightning, but it is presently unknown whether these are actually related to any naturally occurring phenomenon. Scientific data on natural ball lightning are scarce owing to its infrequency and unpredictability. The presumption of its existence is based on reported public sightings, and has therefore produced somewhat inconsistent findings. Because there is a real lack of data on the phenomenon, the true nature of ball lightning is still unknown.
Fire RainbowAlso called a circumhorizontal arc, a fire rainbow is an optical phenomenon formed by ice crystals in high altitude cirrus clouds. If you are very lucky and live at the right latititude, you might see one, possibly two in your entire lifetime. Cirrus clouds are those spread-out, wispy looking clouds that you see way up past the regular, fluffy ones. They are so wispy because there is very little moisture in the air at that altitude.
Despite the fact that cirrus clouds are common, fire rainbows are not. This is for the same reason that you only see a regular rainbow under certain circumstances. The light from the sun has to hit these particular ice crystals at exactly the right angle or the light will not separate (refract) into its colorful components - at least 58 degrees above the horizon. Because of the absolutely specific height of the sun you will not see a fire rainbow south or north of 55 degrees.
Rogue WaveRogue waves (also known as freak waves, monster waves, killer waves, extreme waves, and abnormal waves) are large and dangerous surface waves that occur far out to sea. These are not tsunamis, but instead seem to form from a variety of possible causes.
There are three types of rogue waves, the "Wall of Water", the "Three Sisters" and single, giant storm waves that can collapse within moments of their formation. These waves seem to occur in deep water or where a number of physical factors converge and can cause a number of waves to join together.
Algal BloomAlgal blooms are a natural phenomenon, the occurrence of which may be increased by nutrient pollution. Algae can multiply quickly in waterways with an overabundance of nitrogen and phosphorus, particularly when the water is warm and the weather is calm. This proliferation causes "blooms" of algae that turn the water green, orange or red.
The ones that most folks take note of, of course, are the ones that turn the ocean to blood. Or, you know, "red tide", even though it has nothing to do with the tide. This is known as one of the 'harmful blooms', although not only the red and brown algea are harmful. These HABs can produce neurotoxins (which affect the nervous system) and hepatotoxins (which affect the liver). These toxins can potentially impact the health of people who come into contact with water where HABs are present in high numbers.Even though these blooms have been around since before biblical times, there has been increased public awareness of the negative impacts of these blooms to marine resources -- such as strandings and deaths of marine mammals, birds, and sea turtles. In addition, scientists have determined that there are more toxic algal species, algal toxins, affected fisheries resources, food-web disruption, and economic losses from harmful algal blooms than ever before.
Ice CirclesThat ice circles and discs form is no mystery, but how they form is still a little up in the air. Ice circles are thin, circular slabs of ice that rotate slowly in the water. It is believed that they form in eddy currents, but some new theories involving rising methane have been brought forward in Russia.
PenitentesPenitentes are a snow formation found only at high altitudes. They take the form of tall thin blades of hardened snow or ice closely spaced and pointing in the general direction of the sun. Penitentes can be as tall as a person.
The key climatic condition that leads to the formation of penitentes is that dew point is always below freezing. Thus, snow will sublimate, because sublimation requires a higher energy input than melting. The surface geometry of the growing penitente produces a positive feedback mechanism, and radiation is trapped by multiple reflections between the walls of the points. The hollows become almost a black body for radiation, while decreased wind leads to air saturation, increasing dew point temperature and the onset of melting. In this way peaks and walls remain, which intercept only a minimum of solar radiation and in the spaces between, ablation is enhanced, leading to a downward growth of penitentes. A mathematical model of the process has been developed, but the initial stage of penitente growth, from granular snow to the birth of a new penitente, still remains unclear.