Typhoon Haiyan: Is this a Cat 6 Hypercane?

November 8, 2013

It’s too soon to tell, it will be weeks till the dust settles and things dry out. But Typhoon Haiyan is a monster. Worst ever?
More as it comes in. For now there’s this.

Mother Jones:

By at least one measurement, it appears that Super Typhoon Haiyan, which just slammed into the Philippine island of Samar, may be the strongest storm reliably recorded on Earth. Additional measurements and analysis will surely be necessary to confirm this, but for now, here’s what we know:

The U.S. Navy’s Joint Typhoon Warning Center, which tracks typhoons and Super Typhoons—the most powerful storms on the planet—estimated Haiyan’s maximum 1-minute sustained winds at 170 knots, which translates into about 195 miles per hour.

According to meteorologist Jeff Masters, a number of Pacific storms prior to 1969 were measured with wind speeds equal to or above 170 knots, but these estimates are now considered unreliable. Since 1969, the three strongest storms on record by wind speed all had winds of 165 knots, or 190 miles per hour: 1979’s Super Typhoon Tip, 1969’s Atlantic Hurricane Camille, and 1980’s Atlantic Hurricane Allen. Haiyan just passed all three by this metric, though Masters notes that there is less confidence in Haiyan’s true intensity, since Tip, Camille, and Allen were all investigated by hurricane hunter aircraft. Haiyan’s intensity has only been estimated based on satellite images (you can read more about how these satellite measurements are done, and why Haiyan presented such a stunning satellite image, in this great New Republic article by Nate Cohn).

There are some additional caveats here: Wind speeds are only one way of determining a storm’s intensity. Another is measuring its minimum central pressure, and here Tip still reigns supreme, with a minimum central pressure of 870 millibars.

Most disturbing of all is another record: At landfall, Haiyan was more intense than any other landfalling storm.

Is it possible that Haiyan was a “Category 6” hurricane? Officially, the Saffir-Simpson hurricane scale defines the category 5 range (the highest category) as beginning at 137 knots. But once you’re 33 knots above that, as Haiyan was, perhaps the scale has been superseded. After all, the entire Category 2 range only spans 12 knots.

A senior meteorologist writes:

Sustained winds of 195 with gusts to 230.To put this into perspective an EF-5 tornado has winds over 200 mph. Yolanda is equivalent to an EF-5 tornado, one that’s 40-50 miles in diameter, lasting 2-3 hours. Not sure I’ve ever seen that before…


6 Responses to “Typhoon Haiyan: Is this a Cat 6 Hypercane?”

  1. stephengn1 Says:

    Absolute devastation. I was 7 years old when Camille, a small, but extremely dangerous storm with maximum winds of 185 miles per hour struck 90 miles east of New Orleans. The people in this part the country told horror stories about Camille for decades afterwards. This storm is 5 times the size of Camille and an even faster mover (larger storm surge).

    There is not a single doubt in my mind that the toll will be multiple thousands if it passes over populated areas

  2. omnologos Says:

    “Cat 6” is a recurring journalistic meaningless meme -only useful to spot which journos are into climate p*rn.

  3. “Most disturbing of all is another record …”

    Well, for the super storms of recent years in the world most likely corresponds to the negative (cold) phase of PDO, ENSO and the “pause” in global warming.

    Liu et al. 2004. (http://onlinelibrary.wiley.com/doi/10.1111/0004-5608.00253/abstract): “Remarkably, the two periods of most frequent typhoon strikes in Guangdong (AD 1660–1680, 1850–1880) coincide with two of the coldest and driest periods in northern and central China during the Little Ice Age.”

    Dezileau et al. 2011. (http://hal.archives-ouvertes.fr/hal-00617525/): “The apparent increase in intense storms around 250 years ago occurs during the latter half of the Little Ice Age, a time of lower continental surface temperatures.” “The apparent increase of the superstorm activity during the latter half of the Little Ice Age was probably due to the thermal gradient increase leading to enhanced lower tropospheric baroclinicity …”

    Vecchi et al., 2013. (http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00503.1):
    “The UT [upper troposphere] and TTL [tropical tropopause layer] temperature trends in the NCEP–NCAR reanalysis are unlikely to be accurate and likely drive spuriously positive TC [tropical cyclone] and PI [potential intensity] trends and an INFLATED connection between absolute surface temperature warming and TC activity increases.”

    Thomas Knutson, 2012 (http://www.downtoearth.org.in/content/role-climate-change-tropical-cyclones-still-unclear) says::
    “Yes, but we cannot see a detectable effect of human activity on it. This is different from global rise in temperature, which is a direct consequence of human activity. Looking at projections, increase in intensity will be upto 10 per cent but that’s too small to be detectable now […].” “…IT’S NOT showing any DRAMATIC effects at this point.”
    “We think atmosphere warms more than surface, which STABILISES the atmosphere, leading to fewer storms.”
    “A lot depends on the infrastructure in place, and the geography.”

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