In message . com, "Jack
)" writes
I suspect some mountain wave rotor effect.

Interesting photos.

Jack

Certainly caused by airflow over very rugged high ground. The whole of
the west of Scotland is renowned for the fierceness of squalls at sea in
the lee of high ground, even in winds as low as Force 5-6. There are
many anchorages very popular with yachtsmen that can become untenable
due to the fierceness of the squalls even though they may appear to
offer complete shelter. The sudden high snatch loads induced by squalls
can cause anchors to break out.

Norman.
(delete "thisbit" twice to e-mail)
--
Norman Lynagh Weather Consultancy
Chalfont St Giles 85m a.s.l.
England