On Wednesday, Cyclone Sagar formed deep in the Gulf of Aden, which separates the Middle East and East Africa. The basically unprecedented storm is taking aim at Somalia and Djibouti—a country where tropical weather just doesn’t happen—this weekend. It could bring torrential rain and flash flooding to the area that’s already fairly saturated after a solid wet season, but also have some beneficial effects for the often drought-stricken region over the long-term.
Tropical systems in the gulf are extremely rare. Only seven tropical storms and cyclones have reached the gulf since record keeping in the Indian Ocean began in 1842. Of those, only three have made much headway into its heart. Two of those occurred in 2015, with Cyclones Megh and Chapala bringing widespread flooding to Yemen. The other to penetrate deep into the gulf is an unnamed 1984 storm, which made landfall in Somalia as a tropical storm with 40 mph winds.
Cyclone Sagar has had a bit of meteorological luck on its side to form and track westward into the gulf. The first ingredient for a cyclone to form and strengthen is water in excess of 26.5 degrees Celsius (80 degrees Fahrenheit). That’s plentiful year-round in the Gulf of Aden, and Sagar is currently passing over waters that are 31 degrees Celsius (88 degrees Fahrenheit).
The second ingredient for cyclones is favorable winds in the upper atmosphere. In the Gulf of Aden, good wind conditions (for cyclones anyways) are a rarity. High vertical wind shear, meaning the wind’s speed or direction changes dramatically with height in the atmosphere, tends to tear up storms or stop them from being able to spin up in the first place. But wind shear is anomalously low right now, allowing Sagar to keep churning.
The storm’s winds are about 75 mph, according to the latest estimates from the Joint Typhoon Warning Center. That’s just above the threshold of what would be the equivalent of Category 1 hurricane. The forecast track is a bit to the west of the 1984 storm, and the storm’s cone of uncertainty includes Djibouti, which is located northwest of Somalia and has never been hit by a tropical storm, or even its weaker cousin, a tropical depression, in recorded history.
The rarity of the track means people living in the region could face conditions unlike anything they’ve ever experienced. The arid region receives scant rainfall with Djibouti City, the country’s capital, getting just 18 rainy days a year. Those days accumulate a paltry 6.4 inches of rain, according to the Weather Channel.
Sagar could deliver at least half that amount, and possibly more, in Djibouti. Western Somalia will get even more rain—up to 12 inches this weekend.
That comes as a fairly plentiful wet season that lasts from April-June wraps up. As of May 5, some parts of the region had seen up to 200 percent of their normal rainfall, according to data collected by the Famine Early Warning Systems Network. The blast of rain from Sagar is likely to trigger flooding in those areas, which could complicate the food security situation in the war-torn country.
But the storm could also bring some longer term benefits to Somalia, where 6 million needed food assistance to survive after two years with little to no rainfall prior to this year.
“The food security situation will be complicated because while flooding may be bad (road damage making things inaccessible and so hard to bring food to/from certain places), having additional groundwater later in the season could be beneficial for some crops,” Catherine Pomposi, a postdoc at the University of California Santa Barbara working on food security, told Earther.