XALITZINTLA, Mexico (AP) -- The white-capped volcano that looms over Mexico City emitted a terrifying low-pitched roar Friday and spewed roiling towers of ash and steam as it vented the pressure built up by a massive chamber of magma beneath its slopes. Authorities prepared evacuation routes, ambulances and shelters in the event of a bigger explosion.
Even a large eruption of the 17,886-foot (5,450-meter) cone of Popocatepetl is unlikely to do more than dump ash on one of the world's largest metropolitan areas. But the grit could play havoc with Mexico City's busy airport, and tens of thousands of people in the farming villages on its flanks could be forced to flee.
Popo, as it's commonly known, has put out small eruptions of ash almost daily since a round of eruptive activity began in 1994. A week ago, the eruptions started growing larger and authorities slightly elevated the alert level for people living nearby.