MEXICO CITY — Mexican authorities are preparing evacuation plans for thousands of people living below the giant Popocatepetl volcano 40 miles southeast of Mexico City.
Several Mexican states have reportedly been placed on alert as Popocatepetl — or "Popo" as the 17,887-foot volcano is known locally — spews out ash and molten rock.
The "growing intensity" of the explosions had prompted Mexico's National Center for Disaster Prevention to raise the alert level for the volcano to yellow phase three from yellow phase two, on orders from the country's Interior Ministry, the Los Angeles Times reported.
It is the third-highest warning on the center's seven-step scale.
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At the next stage, the Times cited a statement from the Mexican government as saying, "There is danger. You and your family should be ready for evacuation."
Although the volcano had been spewing out large towers of steam and ash since mid-April, increased activity in the last few days included tremors and explosive eruptions, the Associated Press reported.
Popocatepetl, which means "smoking mountain" in the Aztec language Nahuatl, had shot a plume of steam more than a half mile into the sky, and rocks could be seen glowing in the crater.
Disaster agency experts warn, however, that a lava cap has formed inside Popo's cone, allowing pressure to build toward a bigger explosion.
Officials had created a 7-mile restricted zone around the cone of the volcano, which dominates the landscape of central Mexico along with its "twin," the nearby Iztaccihuatl.
"What we're now seeing, now measuring, can change," Enrique Guevara, director general of the National Center for Disaster Prevention told the Mexican newspaper, Milenio.
"One scenario, for example is that the activity suddenly stops and nothing happens," he said. "There are other scenarios, which we are now dealing with as the most probable, that have the cone growin and leading to a process of destruction."
Some 25 million people live in Popo's shadow, most of them in Mexico City and it's teeming suburbs west of the volcano. But Popo's cone tilts to the east and southeast, meaning any substantial lava flow will spill down that side and toward the historic town of Cholula and the colonial city of Puebla, experts say.
Local, state and federal officials in Puebla and Tlaxcala state have prepared shelters for nearly 12,000 residents of villages on Popo's eastern flanks in the case of evacuation.
Mexico City Mayor Miguel Angel Mancera on Monday announced that emergency brigades have been alerted and more than 500,000 facemasks prepared in case of heavy fallout of volcanic ash should Popo blow.
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How in the world do you pronounce Popocatepetl exactly?
Senior correspondent, Dudley Althaus, contributed reporting from Mexico City.