These pictures were taken last year in Crete. It was in the afternoon when I decided to go on a walk along the beach. It was still sunny and the clouds were relatively bright and very well defined (see: https://callofnatureblog.wordpress.com/2013/05/07/watch-the-clouds-follow-the-dreams/). Then dark clouds came from nowhere and that was the time when it was clear that a storm was coming. In spite of this fact I continued to walk on the beach and take photos with everything I found interesting. Later I went back home and arrived just in time to see the start of the rain.
(mouse over to play slideshow)
Here are some of the “snapshots” I captured during that walk (mouse over to play the slides, for more details click on the below pictures).
Call of Nature 
Great photos, great atmosphere, great clouds over Crete beach… But, why you use D90 instead of D7100?
Thanks for the comment, most appreciated. The photos were taken last year when I still had the D90. I made the upgrade to D7100 2 months ago and can say the difference is big! I will soon post photos taken with the new camera, until now I had few time for editing.