As quickly as it started, the eruption at Grímsvötn seems to be ending. Ash emissions from the volcano ceased early this morning (Iceland time) and now only steam plumes remain at the crater of Grímsvötn (see below). Even yesterday, the plume had dropped below 5 km (from a previous high of 20 km) as the magma discharge rates dropped dramatically (compare the two images below). The Prime Minister of Iceland has said that her country has moved onto the "clean up" phase of the eruption as all signs, such as seismic tremor, suggest that this phase of the eruption is over. You can see some video of the waning stages of the eruption where Surtseyan explosions dominated the activity, thanks to the magma intruding the water in the crater at much lower discharge rates (thus only forming small, < 1 km plumes).
May 25, 2011 (Plume height = 100 meters)