How the ingredients for a catastrophic storm came together for Hurricane Patricia

Hurricane Patricia may be one of the most dangerous storms to ever hit the Western Hemisphere, with winds of 190 miles an hour. William Brangham learns more about the forecast from Bob Henson of Weather Underground.

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    Hurricane Patricia has been described as potentially one of the most dangerous storms to ever hit the Western Hemisphere. Meteorologists now say that Patricia is bringing with it winds of 190 miles an hour, down just slightly from earlier.

    William Brangham has more on the storm itself and what is fueling it. He recorded this interview a short time ago, as the storm was approaching Mexico.


    Bob Henson is a meteorologist for Weather Underground, a Web-based weather service that also has a weekday show on The Weather Channel. Henson is also author of five books on weather and climate change.

    So, Bob Henson, it seems like meteorologists like yourself have run out of terms to describe the intensity of the storm. Yesterday, it was a Category 1. We wake up this morning, it's a Category 5. How did this storm get so big so fast?

  • BOB HENSON, Weather Underground:

    It's a true outlier.

    You know, there's only a very, very few hurricanes or typhoons in world history that we know about that have intensified so quickly. They have really only been observing these systems in depth for the last several decades, say, so we can't really say how strong hurricanes were in 1900 or 1800.

    But, certainly in the modern era of hurricane hunting and satellites, for a storm to go to from a tropical storm to a Cat 5 in, say, 24 hours, 30 hours, those kinds of numbers only happen once in a very rare while. So, this is up in the ranks of maybe the top three or four most rapidly strengthening storms.

    And, basically, it's because it was over extremely warm water that went to some depth, so the winds didn't stir up colder water to weaken it. And upper winds were very weak, which allowed it to intensify rapidly. Really, just all the ingredients came together in just the right way, which, surprisingly, doesn't happen all that often.


    You mentioned that calling this a Category 5, which is the top of the Saffir-Simpson scale, is almost an insufficient description of this storm. Can you explain?



    The Saffir-Simpson scale was developed several decades ago, and it breaks hurricanes down into five bins, Category 1 all the way up to Category 5. Now, most of those bins are about 28-to-30-miles-per-hour-wide, you might put it. Category 5 starts at 156 miles an hour, but it has no ceiling. It's 156 and up.

    This storm had peak winds of 200, so it was 45 miles an hour above the Category 5 threshold. You might say that, if we had a Cat 6 and Cat 7, that it would fall in the Cat 7 range, close to that. We don't parse storms out when they get so strong, in part because once you get to Cat 5, it pretty much destroys everything except a really well-constructed building, so there is not as much operational significance to it.


    So, at that level of intensity, is that what we're expecting that is going to just cause some incredible damage on the coast of Mexico?


    Well, fortunately, it has weakened a little bit as it has approached land. It's still a very, very powerful hurricane, still a Category 5, as in the most recent observations within the last couple of hours.

    Now, the storm surge is going to be pretty significant over a relatively small area. And that's another blessing with this storm. It's not a gigantic hurricane. But there will be an area of a few miles where I would expect very, very severe destruction. And, moreover, when it runs into very steep mountains and hillsides just inland, it is going to be dumping gigantic amounts of rain, again, over not a gigantic area, but there could be tremendous amounts of rain along the way. So, mudslides and floods are also going to be a real issue.


    And then my understanding is that the storm is likely to continue on breaking up somewhat, but then heading into Southern Texas. What are you forecasting for Texas to be looking at?


    Still pretty stout winds. There will be some high water along the Texas coast, but mainly a lot of rain. Could be six to 12 inches of rain in places like Houston.

    And there is an ongoing heavy rain event over Texas already because of a separate storm, so there's going to be some very, very large local rainfall amounts. And Texas is notorious for October systems that bring in tropical moisture and ex-hurricanes from the Pacific. So this is really something to watch as well.



    Bob Henson of Weather Underground, thank you very much.


    Thank you.

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