Typhoon Dujuan crashed into Taiwan on Monday with winds equivalent to those of a category four hurricane. One weather station near the eye reported wind gusts of 153 MPH during the height of the storm. The typhoon also produced more than two feet of rain, forcing the evacuation of thousands for fear of landslides and flooding, closing schools and businesses, and even triggering a water outage for more than a million people in the Taipei area.
(The above satellite loop is 5.40 MB and worth every byte.)
Dujuan followed a similar path to Typhoon Soudelor a month and a half before it, coming ashore on the northeastern part of the island in Yilan County. The intense cyclone was just about as impressive and terrifying as a tropical cyclone can look—its large eye encompassed a significant chunk of the storm right up until landfall, when the eye rapidly collapsed as it started to brush against the island’s rough terrain.
Despite quickly losing its organization as it pushed inland, the typhoon’s winds were ferocious. The small town of Su-ao, very close to where Dujuan made landfall, recorded a 153 MPH wind gust at 6:15 PM local time. Yonagunijima, a Japanese island about 70 miles off the coast of Taiwan, measured a 181 MPH wind gust as Dujuan passed through the region.
Veteran cyclone chaser Josh Morgerman positioned himself in Su-ao just in time to experience the direct impacts of Typhoon Dujuan, and he reported a minimum air pressure of about 958 millibars along with fierce winds that shredded apart a nearby building “like confetti.”
While it’s the most heavily advertised effect of tropical cyclones, wind is only one aspect of their wide variety of impacts. Dujuan was (and, as of this post, continues to be) a prolific rainmaker.
Many locations also saw one to two feet of rain as the typhoon crossed Taiwan. Extensive rainfall in tropical cyclones is bad enough over flat land, but when you take a juicy typhoon and slam it into a chain of mountains, it wrings out every drop of moisture in the atmosphere as the strong winds race up the slopes, enhancing precipitation by two or three times what would have fallen otherwise.
A small town at the foot of the mountains took the brunt of the downpour. Fushan, located west of Su-ao and stuck in the eyewall of the typhoon, has recorded 683 millimeters (26.9 inches) of rain as of 3:30 PM Eastern Time. Most of us have experienced a couple of inches of rain in just an hour, but it’s hard to imagine more than two feet of rain falling in a little over a day. This kind of precipitation can easily trigger life-threatening flash floods and mudslides, not only washing out buildings, but destroying local infrastructure for weeks (if not months) after the storm.
As of this post, a now-lopsided Dujuan is just entering the Taiwan Strait, with very heavy rainfall still making its way across the island. The intense winds and extreme rainfall—not to mention storm surge in coastal areas—likely caused a significant amount of damage and flooding, though the full extent of Dujuan’s impacts won’t be known until the sun rises and conditions improve across the island.
One early indication of widespread impacts is a report in The China Post that the extensive rain and resulting flooding caused turbidity (cloudiness from suspended particles like dirt) in the Xindian River to exceed safe levels, forcing officials to stop water service for to up to a million homes in the Taipei area within the next day.
As expected, the entire northern Pacific Ocean is teeming with tropical cyclones this year. Dujuan is the latest in a string of tropical cyclones to aim for Taiwan and Japan’s Ryukyu Islands in the past couple of months; the island off the southeastern coast of China took a direct hit from Typhoon Soudelor early in August, with a glancing blow from Typhoon Goni just two weeks later.
Dujuan is the 86th name on the western Pacific’s continuous list of 140 tropical cyclone names. Each of the 28 countries that border the ocean basin contribute five names to the list. This typhoon’s name, contributed by China, means “azalea” in English.