|Above: Infrared image of Tropical Cyclone Kenneth at 14Z (10 am EDT) Wednesday, April 24, 2019. Kenneth was nearing the Cormoros Islands at the time, with its eye on track to pass very near the northernmost and largest of the islands—Ngazidja (Grande Comore), outlined near the storm's center. Image credit: CIMSS/SSEC/University of Wisconsin–Madison.
The strongest storm in the history of the Comoros Islands (population 1,000,000)—Tropical Cyclone Kenneth—was pounding the island chain off the southeast coast of Africa with 85-mph sustained winds on Wednesday morning. Kenneth, a Category 1 storm at the time, was headed west-southwest towards the largest island in the Comoros, Grande Comore, with a population of 316,000. On Thursday, the storm will deliver a punishing blow to Mozambique, a nation still reeling from the catastrophic mid-March landfall of Tropical Cyclone Idai. Idai killed over 600 people and brought damages in excess of $1 billion to Mozambique—their costliest natural disaster in history. Kenneth will primarily affect northern Mozambique, which has a much smaller population than the central parts of the country that received the brunt of Idai.
Update: As of the 2 pm EDT Wednesday advisory from the Joint Typhoon Warning Center (JTWC), Kenneth had 115-mph winds, making it the equivalent of a Category 3 hurricane. Kenneth was headed just south of due west at 13 mph. Earlier Thursday, the agency issuing the official forecasts for the South Indian Ocean, RSMC-La Reunion, put Kenneth’s top winds at 80 mph (10-minute average), with a central pressure of 978 mb. Kenneth was under light to moderate wind shear of around 10 knots, over warm waters with sea surface temperatures of 29 - 30°C (84 - 86°F), and had excellent upper-level outflow—conditions very favorable for strengthening.
|Figure 1. Predicted surface winds (colors) at 12Z (8 am EDT) Thursday, April 25, 2019, from the 6Z Wednesday run of the HWRF model. The model predicted that Tropical Cyclone Kenneth would be approaching landfall in northern Mozambique on Thursday at around 12Z (8 am EDT and 2 pm local time) as a Category 3 storm with 125 mph winds. Image credit: tropicaltidbits.com.
Update: As Kenneth approaches landfall in Mozambique, the storm may wrap dry air from continental Africa into its core, potentially causing weakening. In its 18Z Wednesday, update JTWC predicted that Kenneth will make landfall between 12Z and 18Z Thursday as a strong Category 2 or low-end Category 3 storm. An even higher intensity at landfall cannot be ruled out. Two of our best intensity models, the HWRF and COAMPS-TC, predicted with their 6Z Wednesday runs that Kenneth would peak as a Category 4 storm with 135 - 140 mph winds, and make landfall at Category 3 or 4 strength.
If Kenneth makes landfall as a major Category 3 or stronger storm, wind and storm surge damage will be a big concern. Because Kenneth is in the Southern Hemisphere, its clockwise circulation will push the strongest winds and storm surge toward the south of the landfall location. The brunt of Kenneth's landfall impacts may thus end up in the sparsely populated Quirimbas National Park region, including the archipelago of the Quirimbas Islands.
|Figure 2. Predicted precipitation for the period 6Z April 24 - 12Z April 29, 2019, from the 6Z Wednesday run of the HWRF model. The model predicted that Tropical Cyclone Kenneth would bring widespread rainfall amounts in excess of 8" (yellow colors) to coastal northern Mozambique, with a small area of rains in excess of 24” (red colors) along portions of the coast. Additional rainfall is possible beyond April 29 wherever a weakening Kenneth might happen to linger. Image credit: NOAA.
Heavy rains the main threat
Kenneth will be a very wet storm at landfall and will be decelerating, moving at less than 10 mph. The storm is expected to meander just inland after landfall for a day or more, keeping a portion of its circulation over water and thus allowing the storm to dump potentially catastrophic rainfall amounts over northern Mozambique. Kenneth may even re-emerge over the ocean this weekend, allowing regeneration into a tropical cyclone and bringing renewed heavy rains to coastal Mozambique. The 6Z Wednesday run of the HWRF model (Figure 2) predicted that Kenneth would bring a deluge of over 8” of rain to a wide swath of coastal northern Mozambique, with a smaller region of rains in excess of 24” near where the center comes ashore.
The cyclone’s impact could delay the giant natural gas projects Exxon Mobil and Anadarko are planning to start building in Mozambique’s northernmost province of Cabo Delgado later this year. Extreme flooding from Kenneth may also cause severe hardship for an emerging Islamist insurgency with remote bases in forested coastal areas near the Mozambique-Tanzania border.
In a Wednesday update on Kenneth, ReliefWeb noted: "Tropical Cyclone Kenneth is expected to become only the third satellite-era system to evolve to a moderate tropical storm stage or higher in the area north of the Mozambique Channel, according to Meteo France. The other two systems concerned, Elinah in 1983 and Doloresse in 1996, did not reach the African coast. Tropical Cyclone Kenneth therefore threatens an area where the population is not used to cyclones."
|Figure 3. MODIS image of Tropical Cyclone Kenneth taken on Wednesday morning, April 24, 2019. Image credit: NASA.
Comoros Islands tropical cyclone history
The Comoros Islands have very little experience with tropical cyclones, since the islands lie very close to the equator—between 11° and 13°S latitude. According to EM-DAT, the Comoros have endured only three damaging tropical cyclones since 1983. The deadliest and most destructive was Tropical Cyclone Elinah, which passed through the islands as a tropical storm with 45 – 50 mph winds on January 11, 1983, killing 33 people and doing $23 million in damage. All 33 deaths occurred when a huge wave swept 40 people on the island of Anjouan into the water. The last time a hurricane-strength tropical cyclone affected the islands was on February 17, 1996, when Category 1 Doloresse passed about 40 miles to the west of the northern Comoros Islands.
Tanzanian tropical cyclone history
Kenneth is likely to dump up to a foot of rain in southern Tanzania, a nation that has almost no experience with tropical cyclones. According to NOAA’s historical hurricanes database, only two tropical cyclones have ever made landfall in the country: an unnamed 1952 tropical storm, and Tropical Depression Atang of 2002. EM-DAT lists only one deadly tropical cyclone in Tanzanian history, Tropical Cyclone Nadia, which made landfall in northern Mozambique about 120 miles south of the border with Tanzania. Flooding from Nadia killed 4 people in Tanzania.
The aftermath of Cyclone Idai in Mozambique
Tropical Cyclone Idai made landfall on March 14 as a Category 2 storm with 110 mph winds just north of Beira, Mozambique (population 530,000) near the time of high tide, driving a devastating storm surge into the city. Idai also caused enormous wind damage, ripping off hundreds of roofs in Mozambique’s fourth largest city. Since the cyclone was large and moving slowly at landfall, near 6 mph, it was a prodigious rainmaker, with satellite-estimated rainfall amounts in excess of 2 feet in portions of central Mozambique.
The official death toll for Idai on April 23 stood at 1007, with 602 killed in Mozambique, 344 in Zimbabwe, 60 in Malawi, and 1 in Madagascar. Total economic damage to infrastructure in Mozambique alone was estimated at $1 billion (over 8% of their GDP)—their most expensive natural disaster in history. The World Bank estimated that combined damages to Mozambique, Zimbabwe, and Malawi would exceed $2 billion.
As of April 22, Relief Web reported that 73,000 people in Mozambique were living in shelters, and 1.85 million people were in need of assistance. Approximately 6600 cases of cholera had been reported, including at least 7 deaths, but the number of cases was on the decline, thanks to a successful vaccination effort.
How to help
The International Federation of Red Cross and Red Crescent Societies, the United Nations, Save the Children, and the International Medical Corps have targeted donation links so you can help provide food, medical supplies, and shelter to victims of Idai in Mozambique. Doctors Without Borders is also doing great work in Mozambique, and their general donation page is here.
Bob Henson co-wrote this post.