While @eurocontrol has the latest on the airport closures (not likely) and flight cancellations, I was pointed to the Icelandic Meteorological Office and Institute of Earth Sciences, University of Iceland for data on the plume source: i.e. what type of volcano ashes are we facing: From the latest document:
Tephra fallout: The amount of fallout is great from Vík in the west to the east of Öræfajökull. The amount of ash fall is the greatest close to the village Kirkjubæjarklaustur. Ash has been detected in several areas throughout the country, except in the northwest.A sample from Kirkjubæjarklaustur has been analyzed, which was taken around 1h on 22 May. The grains are glassy with micro crystals of plagioclase. Samples well sorted.Whole rock analysis: Basalt, with 50-51 Wt% SiO2Leachate results: 5-10 mg/kg of waterdissolvable flourGrain size distribution: about 10% of the volume of the analyzed samples is finer than 10 micrometer
The Icelandic Met office is here. Updates on the conditions are here.
The London VAAC advisories are here.