The ash cloud emanating from the Iceland volcano is ever changing in form and color, from dove grey to anthracite to brown... and sometimes even blueish when sulfur droplets are present. The form is dependent on the eruption intensity but also on the stability of the surrounding atmosphere. Unstable conditions favour an unsteady plume, even looping, but during high stability acessory clouds tend to acompany the plume, which then forms a billowing sheet downwind affecting visilibity and weather patterns thousands of km away.
This Iceland volcano May 13 update maps linked at the UK Met Office below shows where the plume is most likely headed today, according to the Icelandic authorities:
Update: Additional satellite maps
and aerial photos at Left Coast Rebel
Status report from Iceland -here-