By analysing the September 2013 floods in Colorado, US, the researchers showed that a combination of remote sensing, Twitter and Flickr data could be used to identify flooded areas.

"FEMA (the Federal Emergency Management Agency), the Red Cross and other response agencies use social media now to disseminate relevant information to the general public," said Guido Cervone, associate professor of geography at Pennsylvania State University (Penn State).

After a disaster, response teams typically prioritise rescue and aid efforts with help from imagery and other data that show what regions are affected the most. Responders commonly use satellite imagery, but this on its own has drawbacks.

"Publicly available satellite imagery for a location isn't always available in a timely manner – sometimes it can take days before it becomes available," Elena Sava from Penn State explained.

The findings, published in the International Journal of Remote Sensing, confirmed that Twitter data could serve to identify hotspots for which satellite imagery should be acquired.