The Weather Corner | The earliest super-typhoon ever hit on April 18, and it has climate change written all over it.

We’re bringing you exclusive content from our newsletter, The Forecast, right here on Medium. Sign up for our newsletter here. This story is from our feature called the Weather Corner, where we take a deep dive into weird weather around the world, from our April 21st, 2021, newsletter.

Super Typhoon Surigae, captured by satellites, on April 18. Source: NASA

The strongest tropical cyclone ever recorded in the month of April (or any previous January, February, March, and May, for that matter) tore through the Pacific Ocean last week from April 17–19, prompting severe wind and heavy rainfall warnings and the evacuation of more than 100,000 people and the death of one man along the Philippines’ coast. Experts have already linked the storm’s formation and intensity to climate change.

Typhoon Surigae (known as Bising in the Philippines) officially became the first Category 5 “super-typhoon” of 2021 (that’s when typhoons that have sustained 1-minute surface winds of at least 150 mph). At its peak, winds reached 190 mph, and the storm stretched for 560 miles (900 km), although most of its worst rainy, windy core did not make landfall.

The timing of the storm made headlines, and for good reason: Typhoon season in the Western Pacific generally peaks from July through October, with an annual average of 20 tropical cyclones, eight or nine hit the Philippines. Surigae is the strongest super typhoon ever observed so early in the calendar year.

ln fact, it was also one of the strongest observed at any point in the year: Only four reliably-measured tropical cyclones globally have attained stronger winds ever, according to meteorologist Jeff Masters. The Intergovernmental Panel on Climate Change has said that climate change leads to tropical cyclones with higher rainfall, greater intensity, and greater proportion of high intensity (Category 4–5) storms, as we’ve discussed previously.

The breakneck speed at which the typhoon became so strong raised eyebrows, too. Typhoon Surigae’s winds picked up so quickly from April 17–18, the storm went from a Category 1 to Category 5 in the same 24 hours through a process called rapid intensification (a process we discussed in past pieces), according to NASA. Specifically, the winds jumped up to 180 mph from a mere 90 just 24 hours’ time. For context, the phenomena refers to 35 mph or greater increase in maximum eyewall winds within 24 hours’ time, and this 90 mph spike is close to triple that.

Rapid intensification has always been a phenomenon that storms experience, but it is difficult for forecasters to predict, since it happens so quickly, but certain ingredients tend to help create it: warm sea-surface temperatures, low wind shear (meaning the change in wind by height, because wind shear can blow thunderstorms away from the center of a storm, inhibiting any intensification), and high pressure.

Infrared satellite loop of Typhoon Maria in July 2018, an example of rapid intensification

Climate change increases the frequency and severity of rapid intensification. As we explained when we wrote about 2020’s record-breaking tropical storm season:

Global warming has increased average air temperatures. Much of this heat is then absorbed by our oceans. Tropical cyclones develop and travel over oceans, picking up moisture as they do. Warmer tropical water provides more energy for hurricanes while warmer air can hold more moisture, leading to stronger, more intense storms.

Studies have directly demonstrated this link, as well:

  • MIT hurricane scientist Kerry Emanuel published a American Meteorological Society study in 2017 that noted that storms intensifying 115 mph or more before landfall — a roughly a once-a-century occurrence nowadays — could happen every 5 or 10 years on average by the end of the century.

The increase in storms rapidly intensifying is particularly dangerous when it occurs close to landfall because these warm, moist winds tend to last longer and cause more damage on land. Plus, forecasters can’t warn frontline communities to evacuate on such short notice.

Storm-related disasters pose an extreme risk to farmers and agricultural production, especially those in isolated rural areas and/or on vulnerable islands. Aside from immediate effects like death, injury, hunger and starvation, they can also cause massive infrastructure damage. In terms of agricultural impact, they can wipe out crops, in fields and in storage, kill or injure livestock, and damage homes. Aftereffects such as increased soil salinity post-storm surge or landslide following flash floods can cause land quality and productivity downturns.

Luckily, the path of this hurricane averted a massive disaster. On the other side of the world, though, meteorologists are already predicting an extremely active hurricane season in the Atlantic.

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