Why are flash floods becoming common?

Every summer, we seem to be facing the same shocking scenes. Water sloshing through homes and businesses, cars being dragged from their parking spaces by the rising currents, helicopters lifting horrified families to safety as the grey-brown torrents rise up and snap at their ankles.

Yet again this morning we saw Shropshire hit by weather so dramatic, so horrendously awful that it claimed a human life, and left many people facing the prospect of nights away from home.

Companies shut up shop, schools closed their doors, drivers were pulled from their stranded cars as yet again we prepared to hunker down against the horrifying conditions.

As more rain falls, the landscape seems less well equipped to soak away the flood waters.

Shropshire has seen its share of flooding in the past, Wales was struck by its own rising waters in recent weeks, and Cornwall, Hull, and Cumbria are just some of the UK communities which have been left shell-shocked in the past.

Once again, this summer is becoming memorable not for liberal application of ice cream and sun screen, but for images on television of floods creating havoc for residents and business owners.

But why is this happening yet again? Why is flash flooding becoming such a familiar tale?

Part of the reason – and stop me if you think you’ve heard this one before – is thought to be the rising level of greenhouse gases in the atmosphere.

Carbon dioxide, around 27 billion tonnes of which is released into the atmosphere by humans each year, causes the pores on plants to contract, lessening their ability to soak up water.

It means that a large amount of rain that falls to earth which would be soaked away into the leaves of plants is now left in the ground, lessening the ability of soakaway areas to cope with added rainfall.

That means that when, as we saw today, a month’s worth of rain tumbles down in little more than half an hour, there is little capacity for the land to handle it.

That’s even taking in the amount of green land which can stand up to the pressures of the rain.

Green fields act as soakaway areas to draw off the excess water, but as towns and cities sprawl ever outwards, concrete and tarmac replaces the soft, absorbent fields.

Part of the way that water levels is controlled is by managing the water levels in lakes and reservoirs.

With weather becoming increasingly unpredictable, it can be hard to know whether a controlled release of water is required.

Indeed, it’s not long ago that we were officially in drought. It could be no surprise if water levels were being managed at a higher level as we look to recover and try to prevent droughts becoming more severe in the event of a hot summer.

If so, then there would be little room for all the surplus water that has poured over us in the last 12 hours to stand, and the rivers which feed them would be more liable to backing up.

Work has begun in some parts of the UK to introduce flood defences to help mitigate the effects of the devastating weather conditions which have become a staple of the British summertime in the last decade or so.

Since defences were erected in Shrewsbury, shopkeepers and residents in Frankwell have – touch wood – been spared the shocking site of water lapping over their doorsteps.

Ironbridge has seen a similar investment to help protect against the devastating impact of the most severe of British weather conditions.

But such constructions do not necessarily spare our landscape from disaster. In some cases, the defences can be prone to shoving the waters further up or down-stream, meaning that while the most populated and vulnerable areas can be saved from the damage, the waters are instead displaced.

Indeed, just yesterday the Welsh Assembly scaled back its investment in defences by some £30million.

There is bound, of course, to be more discussion in the coming days and weeks about the impact of climate change on the shocking weather conditions that are blighting our summers.

We can barely escape the images of the receding ice caps, the expansion of the seas because of the increasing temperatures, and the rising sea levels.

The more water that melts and evaporates, the more there is to fall to earth – it’s little wonder that we see so much rain each year.

Spring 2012 seems, at the moment, like a distant memory. The days of March and April, when we basked in record temperatures, appear to have been little more than a cruel tease. Everyone who said ‘this’ll be it, we’ve had summer now’, take a gold star.

Now, yet again, we have passed the longest day of the year with barely a blue sky to show for a washout of a summer.

It all leaves us asking ourselves not only whether we will ever enjoy a sunny summertime again, but whether we can cope, in the long term, with the rising waters.

See also:

• Man dies in Shropshire flooding
• Shropshire struck by floods – LIVE
• Flooding hits Shropshire roads – Videos
• Leader: Tragedy as flood waters take their toll