Chilean Interior Minister Andres Chadwick said: "This doesn't necessarily mean the volcano will start erupting.
"But according to the Sernageomin (National Geological and Mining Service), the volcano is now in a process that could culminate in an eruption, for that reason we've issued a red alert and the evacuation."
More top news
Air pollution released decades ago could still be causing deaths today, according to a new study.
Democrat presidential hopeful Hillary Clinton begins her New Hampshire campaign but young and female voters are opting for Bernie Sanders.
Some southern counties have seen their windiest winds of the winter so far today.