Thursday 15 November, Cyclone Sidr, a category 4 storm spanning 500 kilometres, slammed into south-western Bangladesh. The evacuation by the authorities of 1.5 million people to cyclone shelters built since the devastating floods of 1991 saved many lives. Winds of up to 240 kilometres per hour flattened flimsy straw, bamboo and corrugated iron huts, while waves of 5 metres hit coastal towns like Patuākhāli. Cyclone Sidr also devastated the Sundarbans, the world’s largest mangrove forest, home to thousands of rare animals and a World Heritage Site and Biosphere Reserve since 2001. 
 

Cyclone Sidr left a trail of destruction across a vast and densely populated farming region. The authorities and international aid organizations needed to quickly obtain maps of the disaster areas to organize relief efforts, restore access and identify the cyclone’s impact on livestock and crops. 
 

The SPOT 4 and SPOT 5 satellites were tasked to acquire imagery of southern Bangladesh. The first SPOT 4 scene was received 19 November and made available the next day to member agencies of the International Charter on Space and Major Disasters.
 

Location features and place names—like the town of Patuākhāli (pop. 65,000)—are inserted as a first step. Flood waters appear in blue in the image. Flood zones are delineated and the extent of flood-hit areas is measured. This quick map illustrates the sudden storm surge that swept through the river delta. Patuākhāli is completely flooded.

SPOT 4 delivered imagery of the Patuākhāli flood zone 5 days after the cyclone’s passage. Rapid mapping of the disaster helped teams to assess the impact of flooding and proved a valuable crisis management tool. Given the extent of the disaster, the SPOT satellites have now been tasked to acquire more imagery of Bangladesh.