Weird fog...?

[pluto]

I took these pics, and timelapse, on the coast in Vaucluse in Sydney last night. To the eye it looked like a cloud sitting on the ocean so I decided to run a quick timelapse to see how it moved. Well as you can see it doesn't really move. It was the same shape to the eye as it is in the pics and it didn't move/change shape from when we saw it until we left about an hour later.
The video on youtube is just the timlapse repeated twice and cropped in the second time: http://www.youtube.com/watch?v=Fri6n78nw7s&feature=plcp

Is this just fog? I've never seen anything like it...?

Also the blue streak on the ocean is form the searchlight on a helicopter, I think someone must have jumped from the infamous "The Gap" which is a few hundred metres north of where we were.

EDIT: the timelapse happens over 30mins.

[ourkind]

Very odd indeed, hopefully someone has a plausible explanation, send it to APOD in case it's one of those rare natural occurances ...

[pluto]

Good idea, I might see if someone can identify it first. I was also going to post it to www.theaustralianweatherforum.com and see if anyone there has some ideas.

[SkyViking]

Cool shot, to me this looks like Anticrepuscular rays (http://en.wikipedia.org/wiki/Anticrepuscular_rays). Was there some light source behind you that could have been the source of this?

[pluto]

That's probably it. There was a fairly bright light illuminating some playing fields about 100 metres behind us, I didn't think it would be related as there is a hill with trees blocking it from where we were but I guess it could have been high enough. I'll take a drive past tonight and see if it could've caused it.
Thanks!