Super Typhoon Haiyan, which struck the Philippines on Friday, is being called the strongest storm ever to make landfall, and possibly the most powerful storm recorded in world history.
There’s no doubt that Haiyan was intense. It was equivalent to a Category 5 hurricane as it churned in the western Pacific Ocean, and didn’t lose much strength as it came ashore due to the lack of landforms, such as tall mountains, and other obstacles, like buildings, that would normally slow down a storm of this size.
But due to limitations in measuring techniques, we may never know where Haiyan truly maxed out.
Cyclones, hurricanes, and typhoons all form the same way, but their name changes depending on where they occur. The generic term for all of these storms, which must reach wind speeds of at least 74 miles per hour to be classified as such, is tropical cyclone. A powerful storm that forms over the Atlantic Ocean or eastern Pacific Ocean is called a hurricane. The same storm is called a typhoon in the northwestern Pacific Ocean. That storm becomes a super typhoon when winds hit over 150 mph.
The most reliable way to measure the intensity of tropical cyclones is by flying directly into the storm and dropping weather instruments that measure pressure, humidity, temperature, wind direction, and speed as they fall, according to the New Republic’s Nate Cohn. This method is used by the National Oceanic and Atmospheric Administration for most Atlantic and eastern-Pacific-based hurricanes that could pose a threat to the United States.
But things are done a little differently in the Western Pacific. Tropical cyclone intensity is estimated using satellite imagery, called the “Dvorak technique,” Cohn points out. The most immediate benefit of the Dvorak method is that is can be used where hunter hurricane aircraft either can’t be used or aren’t available. The downside is that it’s not as precise as the data gathered by aircrafts.
Based on satellite estimates, Super Typhoon Haiyan made landfall with winds of 195 mph, according to WunderGround’s meteorologist Jeff Masters.
That exceeds the 190 mph winds sustained by the three strongest tropical cyclones on record since 1969 (we can’t rely on the measurements of tropical cyclones before that time): Hurricane Camille in 1969, Super Typhoon Tip in 1979, and Hurricane Allen in 1980.
All of these storms, however, were measured using hurricane hunter aircraft, while Haiyan’s satellite-based estimates are of “lower confidence,” says Masters.
According to Masters, we also don’t know the central pressure of Haiyan, which is another way to measure tropical cyclone intensity.
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