Cloud-hunters on the lookout for rare clouds may have witnessed strange fallstreak holes and ominous undulatus asperatus clouds. But one of the rarest of them all is the "morning glory wave" cloud, which can be predictably seen in one specific place in the world, and only if the weather's right during a small window of a few weeks during the year.
That location is northern Australia's Gulf of Carpentaria, and it is only seen when there is a change in the air as the atmospheric conditions shift from the dry to the wet season. As Thomas Peacock, a MIT professor of geophysical waves calls it in this Journeyman Pictures documentary below, the morning glory cloud is a "shockwave in the atmosphere of immense proportions. It is a massive line of energy" that stretches as far as 1,000 kilometers (621 miles), travelling at over 60 kilometers per hour (37 miles per hour). Watch this tantalizing look into this spectacular phenomenon:
According to Wikipedia, the morning glory wave cloud is a type of "roll (arcus) cloud" that can stretch wide as far as the eye can see, measure from 1 to 2 kilometres (0.62 to 1.24 miles) high, but located only 100 to 200 metres (330 to 660 feet) above the ground. Known to the local Garrawa Aboriginal people as kangólgi, the overall effect is awe-inspiring -- though not without some risks for the many glider pilots who chase this phenomenon each year:
The Morning Glory is often accompanied by sudden wind squalls, intense low-level wind shear, a rapid increase in the vertical displacement of air parcels, and a sharp pressure jump at the surface. Cloud is continuously formed at the leading edge while being eroded at the trailing edge. Showers or thunderstorms may develop in its wake. In the front of the cloud, there is strong vertical motion that transports air up through the cloud and creates the rolling appearance, while the air in the middle and rear of the cloud becomes turbulent and sinks. The cloud quickly dissipates over land where the air is drier.
Scientists are still not totally sure what causes morning glory clouds. It is still a complex engima, as the physics behind it are not well known, and no computer model can yet reliably predict it. But there are some broad theories: scientists posit that one of the main causes are particular patterns of air circulation created by the sea breezes that develop over the peninsula and the gulf, as well as an expression of the larger weather fronts crossing each other over different air pressures and temperatures in the region.
Though it is primarily seen in the southern part of Australia's Carpentaria Gulf, morning glory clouds have also been reported over the central United States, parts of Europe, eastern Russia, and Winnipeg, Canada, as well as other coastal areas of Australia. Wherever they may been seen, these massive morning glory clouds are a breathtaking show of the raw power at play in nature. More over at According to Wikipedia.