April 11, 2021 - Tropical Cyclones Odette and Seroja off Western Australia

Odette and Seroja

On April 9, 2021, two cyclones jockeyed for position as they raced towards the shores of south-western Western Australia. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of Tropical Cyclone Odette and Tropical Cyclone Seroja on that same day.

At the time the image was captured, Odette was a slightly stronger storm and, with its center located to the northwest, it was spinning clockwise around Serjoa. Both cyclones were affecting the track and the strength of each other.

By April 10, Tropical Cyclone Odette had spun to the southeast of Seroja and merged with it. The enhanced Tropical Cyclone Seroja then intensified as it approached the Western Australia coast. It is forecast to make landfall north of Geraldton at about 1200 UTC (8:00 EDT) on April 11. The Joint Typhoon Warning Center (JTWC) forecast that Seroja will carry sustained winds of about 75 mph (120 km/h) and gusts of up to 92 mph (148 mph) just before landfall. This wind speed places the storm as the equivalent of a Category One storm on the Saffir-Simpson Hurricane Wind Scale and as a weak Category Three storm on the Australian tropical cyclone intensity scale. It is expected to weaken slightly before moving over land.

Unlike the northwestern coast of Western Australia, the southwestern coast rarely experiences cyclones, which means that the region is relatively unprepared for severe storms coming onto land. There is concern that infrastructure, particularly house structure, has not been built to face exceptionally strong wind, high storm surge, and torrential rains. Evacuations are in place for many regions along the coast as Tropical Cyclone Seroja approaches. The storm is expected to weaken quickly once it makes landfall and sweeps across southwestern Australia.

Image Facts
Satellite: Aqua
Date Acquired: 4/9/2021
Resolutions: 1km (1.9 MB), 500m (5.4 MB), 250m (3.8 MB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC