The steam plume from a lava flow moving down the slopes of Eyjafjallajökull on May 2, 2010.

A quick note on the activity at Eyjafjallajökull in Iceland: The ash from the ongoing eruption has caused a partial closure of airspace over Ireland from 0600 to 1200 on Tuesday May 4. This is one of the first closures of European airspace since airspace reopened over 10 days ago. This closure is based on the predicted location of ash in flight corridors over Ireland tomorrow.

The Icelandic Met Office has released two interesting updates on the activity at Eyjafjallajökull. The first describes the current state of the eruption:

The eruption is mixed, with the lava-producing phase being larger than the explosive phase. During the last 2-3 days, the plume has been darker and wider than in the preceding week. Tephra fall-out in the vicinity of Eyjafjallajökull has increased. Dark grey ash clouds are observed over the eruptive site. White steam plumes are rising from Gígjökull, north of the eruption site. The elevation is 4-5.4 km (13-18,000 ft). Clouds of ash at lower elevations were observed drifting south-east of the eruption site. Moderate ash-fall was reported in the village of Vík at noon, Sunday, located 40 km south-east of Eyjafjallajökull.

From the location of the steam plume over Gígjökull, lava has advanced over 3 km north of the eruption. Steam plumes over the glacier edge from 19:40 GMT suggest that lava may have advanced even further. A rough order-of-magnitude estimate of lava volume can be obtained from the dimensions of the ice canyon. This estimate gives a lava production rate of-the-order 20 m3 s-1 (i.e. 50 tonnes s-1). The explosive phase may be 10-20 tonnes s-1.

This update suggests that there is more ash being produced and mentions the lava flows on the flanks of the volcano (see image above). The second update came later today:

Largest eruption plumes were observed at 5-5,5 km height (17-18,000 ft) estimated from the Icelandic Coast Guard (ICG) flight at 14:30. The plume rises higher after large explosions. It is heading east-south-east to south-east from the eruption site.

This indicates why the new ash closures could be predicted as the ash column appears to be taller than in the last week or so. This comes along with the increased meltwater coming from the volcano, noted by a number of Eruptions readers watching the webcams. You can also see a great collection of photos of the effects of the eruption from around Iceland.