Another Record-Breaking Cyclone has Struck Southwest Africa—The Second in Two Months

Tropical Cyclone Kenneth, having struck the southern African countries of Seychelles, Comoro Islands, Northern Madagascar, Mozambique, Tanzania and Malawi, is the record-breaking tenth intense tropical cyclone to strike the Indian Ocean this season, handily breaking the 2006-07 record of just 6 intense cyclones. This storm follows close on the heels of March’s devastating Tropical Cyclone Idai, that made landfall in the same region barely six weeks beforehand. Cyclone Kenneth is responsible for 45 deaths so far, with 38 fatalities in Mozambique alone, and despite the relative calm of the previous two seasons there is concern that high sea surface temperatures in the region—the result of a warming climate—may result in these deadly cyclones becoming far more frequent.

The 2018–19 South-West Indian Ocean cyclone season has so far been the costliest and most active season ever recorded since record keeping began for the region in 1967, and with 1,079 fatalities, it is the deadliest season in over 125 years, second only to the 1891–92 season. Cyclone Kenneth itself also marks a record for the most intense wind speeds at landfall in Mozambique, reaching 220 km/h (140 mph)—the equivalent to a Category 4 hurricane—when it did so on April 25.

“It’s official: Cyclone Kenneth is now the strongest storm to make landfall in recorded history in Mozambique – and in the entire African continent,” meteorologist Eric Holthaus tweeted on April 25.

Kenneth is estimated to have destroyed between 60-80 percent of the staple crops in the island nation of Comoros; 30,000 people, still dealing with the destruction and flooding of Cyclone Idai, were evacuated from the storm’s path in northern Mozambique. Kenneth’s landfall just north of the city of Pemba caused major damage to the city; 90 percent of the homes on Mozambique’s island of Ibo have been flattened, and 2,500 homes were destroyed in Cabo Delgado Province.

But is the severity of the 2018-2019 cyclone season in the South-West Indian Ocean, both in terms of the intensity of individual storms and the sheer number of intense cyclones, a result of global warming?

“We’re always very cautious not [to] pin one particular storm to climate change, but in terms of the pattern of Idai and now Kenneth, there’s this regional intensification of storms that we’re seeing quite clearly,” explains Jennifer Fitchett of the University of Witswatersrand in South Africa, a researcher that is uncovering the link between global warming and the increasing intensity of storms in the region.

Cyclone Kenneth was unique in a number of ways: it is only the second Category-4 cyclone on record to strike Mozambique (along with 2000’s Cyclone Eline), and Mozambique has never been struck by two storms that were Category-2 or higher in the same year since satellite records began. Kenneth also intensified to peak wind strenth in less than 24 hours, leaving virtually no warning that it would intensify past the Category-1 storm that it was initially forecast to become. Kenneth’s track was also unusually close to the equator, a rare place for cyclones to form, due to the coriolis effect being too weak there to impart the spin needed to enable a cyclone to form.

“The further north you move, the less impact you have from Coriolis,” Fitchett explains. “So then the rotation is primarily driven by extreme uplift, which requires very warm sea surface temperatures to induce,” conditions that have been present, not just in the Indian Ocean but around the globe, for many years now.