All this hot dry weather may make people a little complacent about the possibility of flooding. In actual fact, conditions are perfect for surface flooding. When the heavy rain of a summer storm hits ground that has been baked dry, the result is surface water flooding. Let’s take a closer look at why summer is the season of flash floods.
A Quick Lesson in Physical Hydrology
The reason that dry ground is less absorbent than wet ground is all down to the properties of the water droplets and the ground itself. In order for water to soak away, the ground must have a high surface porosity. Dry ground has a low porosity – the water can’t find ‘pores’ through which it could soak through to the substratum of the soil. Instead, it gathers in puddles and pools and eventually runs off. That’s the basics – we’ll save ‘saturated hydraulic conductivity’ for a future blog.
The variable warming of the air above sea and land during the hotter summer months creates the perfect conditions for storms to form. The warm air rises and the water vapour it contains condenses into droplets as the air cools at a higher altitude. If this process happens quickly, the water droplets will form the heavy cumulonimbus clouds that we associate with summer storms.
If the overall warming of the planet that has been recorded by scientists over the last few decades continues, weather events are likely to become more volatile. This means longer dry spells followed by more severe storms. The perfect conditions for surface flooding.
If you think that your property could be at risk from flash flooding, we can help. Our Flood Ark barriers are designed to keep floodwaters out – protecting your property from the devastating effects of flash flooding. To arrange a FREE survey of your property, call us on +44 (0) 1603 879977 or drop us an email to firstname.lastname@example.org.