On 11 January Tropical Cyclone Bansi formed north of Reunion Island in the Southern Indian Ocean and in less than 24 hours had intensified into a category 3 storm.
By January 12 the storm had rapidly consolidated and the bands of thunderstorms circling the centre had expanded. Bands of thunderstorms which were spiralling around the storm, wrapped around it from the northwest to the southeast and finally wrapped into the centre from the west.
According to the Joint Typhoon Warning Center (JTWC) as of 06:00 UTC on 12 January, the centre of Bansi was located close to 17.25°S 55.9°E, approximately 350 km northwest of Mauritius, with maximum sustained winds of 185 km/h, equivalent to a Category 3 storm on the Saffir-Simpson Hurricane Winds scale (SSHWS), and was tracking east at 13 km/hr towards the island archipelago of Saint Brandon. Hurricane force winds were extending 56 km from the centre of the storm, while tropical storm force winds were extending outwards up to 195 km.
IODC Visible (0.7)
Download VIS animation 11 January 02:30 UTC–15 January 10:30 UTC (MP4, 12 MB)
Download animation, 10 January 12:00 UTC–15 January 12:00 UTC (MP4, 50 MB).
13 January activity
By the morning of 13 January Bansi's maximum sustained winds had reached 260 km/h, equivalent to a Category 4 storm, with gusts of more than 300 km/h.
Downloaded zoomed-in version
The high winds speeds can be seen on the Metop-B image with ASCAT winds overlaid from 13 January, 05:45 UTC.
15 January activity
Later on 13 January the storm started to weaken slightly, but on 15 January started to re-intensified into a Category 4 storm, bringing high winds and heavy rainfall to Mauritius. As it intensified again the eye of the storm quadrupled in size, as can be seen in the zoomed-in infrared image right.
16 and 17January activity
The visible imagery from Meteosat-7, 16 January 07:30 UTC, shows another tropical system, Tropical Cyclone Chedza, over the Mozambique Channel. The distinct eyes of both storms can be clearly seen in the image. The infrared animation, Meteoesat-7, 10 January 00:00 UTC– 18 January 06:00 UTC (MP4, 23 MB) shows the progress of both cyclones.
Tropical cyclone Chedza passed over Madagascar on 16/17 January, leaving at least 14 dead and causing severe floods and landslides.
Mauritius braces for tropical storm (Global Times)
Tropical Cyclone Bansi in the Indian Ocean (CIMSS Blog)
NASA-NOAA's Suomi NPP Satellite Sees Tropical Cyclone Bansi's Eye Almost Quadruple in Area (NASA)
14 Killed, Thousands Displaced by Madagascar Tropical Storm (ABC News)
Real-time storm coverage (SSEC, University of Wisconsin-Madison)