I had a dream once – I was walking along a river in China and then an audible alarm emitting from my mobile phone got my attention. When I looked at the screen, surprisingly, a symbol with a red border showing rising water and a human figure running uphill towards shelter, was displaying. Later I realized, being illiterate in Mandarin, a text message would have done me no good. However, the symbol made perfect sense. It was an immediate threat of a sudden-onset flash flood (possibly caused by a damn burst).