Volcanic Ash Clouds, Summer 2009

On June 12th 2009, the Sarychev volcano in Russia erupted, sending plumes of fine ash into the stratosphere. This ash then spread across the Northern Hemisphere to give spectacular sunsets throughout late June and July. See here for more. I first heard of the event when I looked up ash clouds on the 27th June, as I had noticed some unusual clouds around sunset. They can be seen here between the lower level, darker clouds:

On the 4th July, clear evening skies revealed an extensive display, stretching from NE to SW, with details becoming visible as the sun lowered towards the horizon:

After sunset, the ash began to take on the famous volcanic hues of orange and purple:

The effects of the ash can vary according to lower atmosphere weather conditions etc. On 15th July, rather than revealing detail in the ash veil, the sunset provided a bright 'afterglow', similar to that produced by polar mesospheric clouds. This occurred about 15 minutes after sunset:

On the 17th July, the cloud was still clearly visible, with very fine bands running NE to SW across the sky:

The ash was still visible up to at least the 29th July, and will probably continue for a few more weeks.