Guatemala's Santa Maria volcano with the dome complex visible in the foreground.
I got a tip the other day from an Eruptions reader of something afoot at Guatemala's Santiaguito - a part of the larger Santa Maria volcano - and sure enough, there are reports today that the volcano is experiencing an "unusual and violent" display. The articles I can find only mention that ash was spread over six provinces in the western part of the country, which is unusual for this volcano that normally produces diffuse ash plumes and minor dome collapse avalanches (at least in the recent past). The Institute of Seismology, Volcanology, Meteorology and Hydrology (Insivumeh) placed the volcano on Orange alert status due to the number of explosions and earthquakes, along with the 8.5 km ash plume that was produced yesterday. Authorities have closed schools and warned people to avoid outdoor activity while the ash is in the air.
The volcano is capable of producing deadly eruption, with 2,500 people killed in a 1929 eruption when pyroclastic flows from a dome collapse traveled 10 km from the volcano into surrounding villages. However, since then pyroclastic flow activity has become much rarer.
UPDATE 1: If you want all sorts of details on Santiaguito, check on Magma Cum Laude. I've also added a MODIS image taken yesterday of the wispy plume of the volcano (see below).