Hypercane

A hypercane is a hypothetical class of extreme tropical cyclone that could form if ocean temperatures reached around , 15 °C higher than the warmest ocean temperature ever recorded— which could in turn be caused by a large asteroid or comet impact, a large volcanic or supervolcanic eruption, or very extensive global warming. There is some speculation that some dinosaurs might have been killed off by a series of hypercanes, resulting from an asteroid or comet crashing into Earth. The term was coined by atmospheric scientist Kerry Emanuel in 1994, at MIT.

Physical description

Hypercanes would have wind speeds of over , and would also have a central pressure of less than , giving them an enormous lifespan. The extreme conditions needed to create such a storm could conceivably produce a system up to the size of North America, creating storm surges of and an eye nearly across. The waters could remain hot enough for weeks, allowing more hypercanes to be formed. A hypercane's clouds would reach into the stratosphere. A hypercane would also damage the earth's ozone. Water molecules in the stratosphere would react with ozone to accelerate decay into O₂ and reduce absorption of ultraviolet light.

Other scientists have theorized that the system, compared to a normal hurricane, would be considerably smaller, about 10 miles in diameter. This would be more comparable to a tornado, which has been recorded at up to about 2.5 miles.

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