Cenapred works with different alert levels set out in the Volcanic Alert Semaphore, which shows the volcano's intensity through colors: green (normal intensity), yellow (warning) and red (alarm). In turn, the yellow level - which means people should remain vigilant and be ready for a possible evacuation- is divided in three phases. Phase 2, which means there is an increased activity, has the following characteristics: water vapor and gas plume, light ashfall in nearby areas, the fall of incandescent fragments, possible pyroclastic flows due to explosions and short range mudflows or debris.
There are low intensity exhalations and some low intensity explosions. Yesterday, the volcano emitted water vapor and gases in a constant manner. The volcano has created ash clouds that are nearly 2 kilometers high. Mexico has many volcanoes but only 14 of them, including the Popocatepetl, are active. This 5,450 meter high volcano often ejects ash.