[Andy Mayhew]

Dave W, on 10 June 2012 - 17:34, said:

Breaking news- Pennal, Gwynedd being evacuated over dam breach flood risk
http://www.bbc.co.uk...-wales-18387520

Apparently all is now okay.

I just can't find the dam - presumably it was a small levee round mine workings? Too small to appear on any map or on google earth? Odd.

[smartie]

John Mason, on 10 June 2012 - 12:24, said:

Blog-post: http://www.geologywa...s/summer12a.htm

Worth following the links from the end of the post, too. Cheers - John

Thanks for the post John.

It's highly likely the rainfall was enhanced by the'Feeder-Seeder Mechanism' ie ice was falling from higher level Cirrus cloud into the lower layers increasing ppn efficiency. The Ci would naturally be associated with the back-bent front, but may also have been enhanced by cloud generated by the terrain upwind- Ireland. As the front was orientated ~normal to the mountain range a number of factors may have conspired to produce the high totals.

David

[John Mason]

Hi David,

Interesting, though at the same time I can't see how this seeding mechanism would account for very little rain over the Irish Sea yet tons over the mountains, which is clearly what occurred. Could you explain in more detail please??

Cheers - John

[smartie]

John Mason, on 10 June 2012 - 21:19, said:

Hi David,

Interesting, though at the same time I can't see how this seeding mechanism would account for very little rain over the Irish Sea yet tons over the mountains, which is clearly what occurred. Could you explain in more detail please??

Cheers - John

I'll start a thread in SA&D.

D

[Dave K]

A postscript to the flooding in Ceredigion

Quote

Wales floods: Mines pollution fear investigated

Scientists are to investigate whether severe flooding near Aberystwyth has contaminated land with harmful metals from abandoned mines.


http://www.bbc.co.uk...-wales-18391758

When I was young and being dragged aroung visiting relatives I explored around the safe areas of the old mine workings near Aber, could still pick up good samples of galena and pyrites.

[skanky]

Big Dave, on 12 June 2012 - 09:18, said:

A postscript to the flooding in Ceredigion



When I was young and being dragged aroung visiting relatives I explored around the safe areas of the old mine workings near Aber, could still pick up good samples of galena and pyrites.

I expect JM can add to this.
I was just reading this page yesterday: http://www.geologywa...heidol-mine.htm

[John Mason]

Just a quick follow-up to this thread - was walking in the Llyfnant Valley this morning, which I used to get through to Talybont on June 9th, and turned up the no-through-road to Cwmrhaidr Falls. A little way up there I came across the most spectacular landslide I have seen hereabouts, and judging by the dieback on the many mature conifers that were piled like jack-straws at the valley-bottom, it must have occurred a couple of months back at least. Suspect this was connected to the June 8-9 event. Have taken photos and will post a link next time the blog gets an update in a week or two.