Flash Flooding West Midlands 16th June 2016

[Costa Del Fal]

Yesterday brought quite easily one of the greatest rain and thunder storms I have ever encountered and one which I don't think I will see again or a very long time. 

All afternoon an area of rain was persistent just to our south whilst it remained dry here. Some will remember me commenting that it looked dry for the rest of the day here with nothing forming in a large zone from Lincolnshire to the W Midlands conurbation. Well, that rain to our south seemed to expand slightly this way and just became more and more intense. Watching the radar was really quite something, witnessing backbuilding to an extent and persistence I have not seen before, certainly at least in these parts. A constant stream of torrential precipitation seemed to originate over Dudley and push over Brierley Hill, Cradley, Quarry Bank and Stourbridge. As these cells developed, they eventually became thundery. There were numerous overhead flashes and long, deep booms of thunder. I think the lightning was mostly CC although I cannot say I took much notice as the rain was the real feature and being directly overhead, I could have missed any CG strikes. 

The rain drops were always of tropical size too and were huge. In a short space of time the roads were fast becoming rivers and it was all pooling up in any dips the water could find. One of these spots was by Saltwells Nature reserve for those who know it. Roads around The Delph, Brierley Hill and Merry Hill shopping centre were also extremely bad with shops closing early. 

Below are some of the pictures from my road last night along with the stream which rose so high which should just pass under my road through a culvert. However the shear amount of water meant it rose a significant number of feet and went over the road instead - something I have never seen before.

Here was another street just around the corner...

It certainly proved chaotic as people were just being diverted to streets which were also flooded, leaving many stuck and pondering how to get home. The council did it's best putting up road closed signs though I suspect they were running out of them with the number of incidents going on!

This morning and the streams through the nature reserve are still rather dangerous albeit the levels have dropped. However it has revealed destruction, damage and the vast extent of the floods.

Sadly, one path was completely washed away in the reserve to the power of the flood water and removed a significant extent of land, exposing the bare rock underneath. The reserve here used to be a significant mining site. The flow of water here is usually gentle and wading depth but last night, there was clearly a massive flood with such a force. I never expected to see the damage seen today and I am left stunned. It was clearly a very dangerous place to be with major erosion and scour in action. Conservation efforts which have included fencing made of old tree branches and new pathways have been destroyed. 

Footbridges have been left undermined with severe erosion around their banks...

Here, was once a path, once surrounded by woodland on its fringes. Now taken over by the water which clearly swept away a massive amount of land... remember of all of this in an area where the streams are usually quite gentle on your average day...

 

Further walking through the Saltwells Nature Reserve and on towards Mousesweet Nature Reserve, along the Black Brook reveals further incredible damage. Vegetation flattened, trees ripped up, fences ripped up and piled up against another fence, fences/gates covered in silt. In particular note in some photos where the vegetation on it's lower half is grey in colour and green at the top. A testimony to the height of the flood and the silt it contained. The grey colour again representing the deposit of silt.

 

So, in summary, some quite incredible images. I am particularly keen to know why such backbuilding of the storm was so persistent over us yesterday. It was clearly localised but was there a small area of convergence overhead? I thought the main convergence was to the south and east of us yesterday. Did the winds from the north (what little there was of it!) and hilly topography to our north over the Black Country aid in the resultant downpours on the southern edge of the W Midlands conurbation where we are?

Any answers greatly appreciated. Also please feel free to share your photos and any information you have here too.

 

 

[I remember Atlantic 252]

 It reached as far NW as Rugeley, but not this far

Edited June 17, 2016 by I remember Atlantic 252

[RobR]

Great images and story. I was watching the radar at the time and thinking you were getting pummeled under there. A very unique situation for our country!

[Terminal Moraine]

I looked at the NW rainfall radar accumulation map the following morning and there was a quite large area containing the places you mentioned with 60-70 mm of rainfall indicated. A few smaller areas showed 70-80 mm and there was one area, I think it was just to the west of Brierley Hill, with more than 90 mm indicated.

Impressive photos and, as you say, probably a once in a lifetime experience although judging by the experience of people in Cumbria in recent years you never know.

[Supacell]

A fantastic account of the damage caused by flooding as a result of some intense thunderstorms, much like has occurred in various parts over this past week or two. I will attempt to explain from my knowledge what may be to blame.

The nature of the storms this past week was for them to form along convergence zones in an environment of slack winds at all levels (no wind shear but also very little storm motion), moderate to high CAPE and very high levels of moisture. This is a recipe for big storm clouds to shoot up and produce excessively heavy precipitation. Then, when one storm forms and collapses it sends out outflow which in turn provides a trigger for more storms to form and go through the same procedure. If nothing is moving, then the convergence zone remains in the same place and the storms form, mature and collapse along the same line and in around about the same place. 

If we get pulse storms with some movement of the air then we get the classic scattered thunderstorm situation where a few people see a storm but most don't. This is the frustrating scenario all us storm nuts know well. When you see a storm erupt on radar, produce numerous sferics and then die out just as it approaches. The same storm then reignites just a few miles down the road! Well imagine that same thing happening but nothing is moving.... you get thunderstorm, an almost lull in proceedings and then another thunderstorm but all in the same place. Meanwhile, somewhere just a few miles down the road may then wonder what all the fuss is about.

Last week was a classic situation of some places getting an absolute deluge where others got very little. 

 

[Costa Del Fal]

Thanks for the above information both. Supacell, sounds about right. I was just a bit puzzled as I didn't think a convergence zone was expected here though perhaps it was a small one. The centre of the low still was not far away after all.

really quite a phenomenal evening. The landscape in the woodland here has potentially been changed forever in places. All from a stream which usually is about no wider than 6-10ft and no deeper than about 1ft on average. Phenomenal increase in such a short space of time.

[Costa Del Fal]

Found a great twitter feed of an Environment Agency flood cam at Mushroom Green in the area where the Mousesweet Brook and Black Brook meet near me. Images are posted every few hours (daylight only in general). Here it is: https://twitter.com/B645BX?ref_src=twsrc^tfw

Go to the 16th/17th June. It gives a great overview of how clear the trash screen and surrounding area was all clear and in good condition until late afternoon on Thursday. Then the water rises very high coming some way up the camera pole with water covering almost the whole image. And now what is left is so much debris washed down in the powerful flood. Incredible. 

[Costa Del Fal]

Does outflow causing backbuilding always tend to occur where the cell once was? I.e the cells here were very slowly travelling north to south so would they always build to the north? Could outflow have generated new cells to the west and east too?