Super Typhoon Haiyan, Uncertain Pressure

17 11 2013

On November 7 an extremely powerful typhoon hit The Philippine Islands and caused a massive amount of destruction and chaos.  As of right now, Nov. 17, 3,714 people have been confirmed to have perished with the damage toll over $1 billion.  One of the most memorable images that has been seen across the web is this one:

A classic buzz saw image of an extremely intense tropical system.

One thing to keep in mind is that this is in the Pacific Ocean which is a much larger body of water and less land interaction for the storms to hit so it is fairly common for them to get very powerful.  There was a brief time where someone superimposed an image of Super Typhoon Haiyan onto a small map of the United States making it as big as the U.S.  This is false.  No tropical system could be that big.  However, it has been compared to a notorious storm that everyone in the Southeast Region of the U.S. are very familiar with.

It is clear to see that Hurricane Katrina had a larger eye than Super Typhoon Haiyan, but Haiyan is much broader than Katrina.  This image shows that Haiyan is no where near as big as the U.S., but if it made landfall on us it would have been horrendous.

To compare Haiyan to one of our hurricanes it had max 10 minute winds of 145 MPH which is comparable to Hurricane Earl or Hurricane Ike.  The strongest 1 minute winds estimated from Haiyan was 195 MPH.  The most notable hurricane in our neck of the woods to have winds close to that was Hurricane Camille at 190 MPH.  Those of you who lived through Camille can imagine what it was like to deal with what the people of the Philippines had to deal with.

The amazing thing about the storm is the lowest pressure the storm ever got to.  Satellites estimated that the lowest pressure that Haiyan reached was 895 millibars.  That is not the lowest pressure ever recorded from a tropical system since we know that Hurricane Wilma is the lowest pressure recorded in our tropical region of 882 millibars.  There are some discrepancies with Super Typhoon Haiyan’s low pressure.  For one, it’s estimated by a satellite to be 895 millibars.  Satellites are good, but not precise in their use.  The other is measurements that were taken on The Philippine Islands as Haiyan was making landfall.  A group of storm chasers called iCyclone took some measurements while they were in Tacloban and the lowest pressure they measured was 960.3 millibars.  The Tacloban airport, just one mile south of the storm chasers location, measured 955.6 millibars before power went out.  Both the measurements were taken almost at the same time with only a 5 minute difference and were taken as the center of Haiyan was just passing south of them which means it was the lowest pressure each measured.  By performing some simple math, between those two measurements is a 4.7 millibar difference in just 1 mile.  The airport was just 17 miles north of the center of the storm.  If the change in pressure was 4.5 millibars to 5 millibars per mile like what was measured from the iCyclone crew and the airport, that means the lowest pressure of Haiyan would range somewhere between 879 millibars and 871 millibars.  This would put Haiyan in the top 5 most intense tropical cyclones in the world.  This pressure estimate makes sense because the other typhoons within the range what Haiyan could be had max 1 minutes winds ranging from 190 MPH to 200 MPH.  The most intense storm in the Pacific Ocean is Super Typhoon Tip which had a minimum pressure of 870 millibars.

Other than the unknown official minimum pressure of Haiayn, the next unknown bout Haiyan is whether or not it’s the strongest tropical cyclone to make landfall in recorded history.  It is currently the second deadliest typhoon to hit the Philippines on record.  The deadliest was Tropical Storm Thelma, or Tropical Storm Uring in the Philippines, which killed somewhere between 5,000 and 8,000 poeple.



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