Cloud Formations from Pia

Pia sent us an email with photos of the same cloud formation Malcolm had photographed. She added this information:

I was looking out the window tonight (Friday 8th June at approx 22.20) when I noticed this cloud formation, see photos.

Not being an expert in cloud technology I consulted the net and according to http://www.collthings.co.uk/2008/06/10-very-rare-clouds.html

these could be "roll clouds" - and I quote:  A roll cloud is a low, horizontal tube-shaped arcus cloud associated with a thunderstorm gust front, or sometimes a cold front. Roll clouds can also be a sign of possible microburst activity.

Thanks Pia!