Social media can warn us about hurricanes, storms and floods before they happen, according to new research. Key words and photos on social media can signal developing risks – like water levels rising before a flood, say investigators. Found certain words – such as river, water and landscape – take on distinct meaning of forecast and warning during time periods leading to extreme weather events. Words can be used as ‘social sensors’, to create accurate early warning system for extreme weather, alongside physical sensors, the researchers conclude.