Heavy rainfall dumped by Medicane Cassilda (Ianos) visualized

Medicane Cassilda, known as Ianos in Greece, formed on September 16, 2020, as the first named storm of the 2020/21 Mediterranean medicane season. 

Cassilda made landfall in Argostoli, Kefalonia, western Greece at 02:20 UTC on September 18, bringing powerful winds and very heavy rain.

At the time of landfall, Cassilda had maximum sustained winds of 110 km/h (70 mph) and gusts to 135 km/h (85 mph).

The storm caused widespread infrastructural damage, downed trees and bridges, disrupted traffic, damaged roads, homes and buildings, sank boats, and left thousands of homes without power. 

At least 3 people have been killed, one person is missing and nearly 1 000 had to be rescued.

Ionian Sea islands of Zakynthos, Kefalonia, and Ithaca, and areas around the cities of Kardiutsa and Farsala in central Greece are among the worst hit.

According to official estimates, 5 000 properties were flooded in Karditsa alone.

The storm moved through central Greece after striking the Ionian islands and exited back into the Mediterranean Sea.

In the animation below, blue/yellow shading shows IMERG algorithm rain rates throughout Cassilda's path, with yellow indicating high values (>25 millimeters/hour; 1 inch).

Animation credit: NASA/GSFC, Jason West

Image credit: NASA/GSFC, Chris Kidd

White/gray shading shows cloudiness based on NOAA infrared satellite observations.

Green shading shows the IMERG rain accumulations that resulted from Cassilda's passage.

The yellow line shows the approximate location of the storm’s low-pressure center, based on output from NOAA’s GFS model analysis.

By 23:00 UTC on September 20, IMERG estimated that the storm left rainfall accumulations in excess of 150 mm (5.9 inches) in central and western coastal Greece and 300 mm (11.8 inches) in parts of the Ionian Islands, in particular Kefalonia.

Featured image credit: NASA/JAXA, GPM/IMERG