Brief note about events in Mexico: It appears that the activity at Popocatépetl has picked up, with more ash emissions and even (unconfirmed) reports of new lava at the summit. This would all suggest that the potential for a significant eruption is high. A report from the BBC says that volcanic bombs are being thrown over a kilometer from the vent and "60 opening" have appeared on the volcano. I actually have no idea what that means - are there cracks at the summit or just lots of fumarolic activity near the summit crater? The explosions from the volcano have been large enough to rattle windows in communities surrounding the volcano. CENAPRED reported over 12 explosions in two hours starting at ~5 AM on Friday (April 20). The steam-and-ash plume from Popocatépetl topped out at ~3 km / 10,000 feet while seismicity remains at elevated levels. CENAPRED currently has the warning level at Yellow Level II with a 12-km exclusion zone around the volcano - in that same report, CENAPRED geologist Roberto Quaas suggests that they are concerned about a potential cycle of dome growth and collapse at Popo, heightening the threat of pyroclastic flows. However, exactly when or if a large eruption might happen cannot be predicted. It appears that there are some issues about people taking this activity at Popo seriously, though. In an article from USA Today, a local resident is quoted as saying "Right now we're not scared. When it's scary is at night, when it's putting out lava." (see above) Well, the lava is there when its not night, so the threat is persistent, day or night. Officially, evacuations have not been called. However, government officials are telling people to be ready to evacuate and to watch the volcano for signs of increasing activity. All this news about the reaction of people living near the volcano makes me nervous, especially when I read about people near the volcano choosing not to leave when the threat is present. Mexican president Felipe Calderon called on the populace to be prepared as well.
NASA posted a short movie of the ash from Popocatépetl seen on April 18, 2012 - the puff from the volcano is clearly seen spreading across central Mexico. All in all, it looks like we're entering a period where everyone, especially those living near Popocatépetl, need to watch the volcano very closely.