TROPICAL Cyclone Idai has ravaged the eastern border city of Mutare, blowing off roofing sheets and damaging both trees and vehicles in its wake. Idai already been named the deadliest weather disaster of 2019 throughout the whole world, with 122 deaths as at Friday.
The Cyclone is expected to bring heavy rainfall and strong winds across the whole country between today and Sunday, according to weather forecasts.
Weather experts at NASA have forecast that Idai will bring highly destructive winds and heavy rains of 1 – 2 feet as it pushes west at about 12 kmh towards Zimbabwe through Friday night.
Idai will likely die on Friday night over the high terrain along the Mozambique-Zimbabwe border, but its remnants will generate very heavy rain through the weekend.
Idai’s heaviest rains may exceed two feet in the higher terrain along the Mozambique-Zimbabwe border, according to recent runs of the HWRF model. Idai’s rains will likely cause catastrophic flooding in some regions.
The disturbance that developed into Idai originated in Mozambique earlier in March, when it caused flooding in northern parts of the country and in neighboring southern Malawi. Cuamba, Mozambique received 11.14” of rain in just 12 hours on March 7. At least 66 were killed by flooding in Mozambique and another 56 lost their lives in Malawi. This makes Idai the deadliest weather disaster so far in 2019, ahead of the 80 people killed in January flooding in Indonesia, according to statistics from insurance broker Aon. Idai’s floods have displaced 100,000 people and injured 688.
|Figure 1. Predicted surface winds (colors) at 21Z Thursday (5 pm EDT) March 14, 2019, from the 12Z Thursday run of the HWRF model. The model predicted that Tropical Cyclone Idai would be a Category 2 storm with 105 mph winds, making landfall near Beira, Mozambique. The clockwise flow of air around Idai brought a worst-case storm surge at high tide into the funnel-shaped bay on the west side of Beira, thanks to the strong southerly winds in the west eyewall of the storm. Image credit: tropicaltidbits.com.|
A storm tide of up to 13 feet above high tide may have occurred
Fortunately, Idai hit during some of the lowest tides of the month. In locations where Idai’s storm surge was 7 feet, the peak water levels would have been near what the normal high tide will bring on March 20, due to the phase of the moon.
Anything over a 7-foot storm surge would have been trouble, and RSMC-La Reunion warned with their 18Z Thursday advisory that Beira could expect a storm surge of up to 13 feet (4 meters), with a much higher storm surge over 20 feet (6 meters) at the mouth of the Pungwe River, which forms the western boundary of the city. The bay that the river flows into is funnel-shaped and shallow, which very likely allowed a huge storm surge to build up, since the dangerous southern portion of the eyewall moved over it for several hours.
A sea level rise of 1 meter will flood 40% of the town (42.5 square km), including the port and the airport. Beira’s port is the second busiest in the nation, and has long been a major trade point for exports coming in and out of Zimbabwe, Malawi, Zambia and other Southern African nations. According to a January article in Aljazeera.com, Beira is steadily sinking, and portions of the city now lie below sea level.