“She didn’t even know what she’d do when she got back to New Orleans, but inside she felt a yearning to shove her hands in the dirt, to cling to the ground there, forever.” -Sarah Rae

Hurricanes are among the most destructive natural disasters to occur on Earth, with extensive flooding, property damage and loss of life commonly accompanying them. But they’re also inevitable consequences — at least on our world — of two simple factors: warm ocean waters and winds.

The formation of a hurricane relies on warm, humid air, winds, and pressure changes. Image credit: NASA's SciJinks, via http://scijinks.jpl.nasa.gov/hurricane/.

The formation of a hurricane relies on warm, humid air, winds, and pressure changes. Image credit: NASA’s SciJinks, via http://scijinks.jpl.nasa.gov/hurricane/.

Thanks to the physics of temperature, pressure, phase changes and air flow, the development of tropical cyclones during the right time of year is unavoidable. Most of them will turn out to be harmless to humanity, but under the right conditions, catastrophe can ensue.

National Hurricane Center forecast as of 5 pm on October 4th. Image credit: NOAA.

National Hurricane Center forecast as of 5 pm on October 4th. Image credit: NOAA.

With Hurricane Matthew on its way to the eastern United States, it’s time to learn the science of how they work!

Comments

  1. #1 Anonymous Coward
    October 5, 2016

    I wonder what tropical cyclones were like in, say, the Devonian period (around 400 million years ago), where mean surface temperatures were in the range of 30°C (compared to 14°C today), and atmospheric CO2 levels were eight times preindustrial levels, and most of the major continental landmasses were clustered together and surrounded by a world ocean. The earth must have experienced tropical cyclones of a power that would dwarf those of today. All of the main ingredients for making powerful tropical cyclones were present in much greater quantities then.

  2. #2 Naked Bunny with a Whip
    October 6, 2016

    Would hurricanes form if there were no land masses? (I don’t know how much the presence of land contributes to the needed winds.) Would they ever go away?

  3. #3 Michael Kelsey
    SLAC National Accelerator Laboratory
    October 6, 2016

    @Bunny #2: Yes and yes.

    Hurricanes form (from intensification of tropical depressions to tropical storms to hurricanes) over open ocean, essentially as a result of energy transfer from warm water to atmosphere.

    They degrade over land masses where that energy source isn’t present, and also degrade over water as they move to higher latitudes and colder waters.

  4. #4 Naked Bunny with a Whip
    October 7, 2016

    Ah, right, the higher latitudes. I didn’t think of that. Thanks, Michael!

  5. #5 Sinisa Lazarek
    October 8, 2016

    re: #2

    Jupiter comes to mind.. gas planet, no land, yet huge storm

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