Experiment Shows Risk of Flash Flooding After Drought

British University Experiment Shows Risk of Flash Flooding After Drought
An experiment by a scientist at England’s University of Reading seeks to show how the risk of flash floods increases from heavy rain after a period of drought.
Dr Rob Thompson uploaded a video to YouTube this week showing that it takes longer for water to soak into dry grass after a heat wave than into wet grass or grass in normal summer conditions.
The experiment “shows just how long it takes water to soak into parched ground, illustrating why heavy rainfall after a #drought can be dangerous and might lead to flash floods,” the university said on its Twitter account.
The video shows three clear plastic cups filled with water, on patches of grass mimicking wet grass, “normal summer” grass, and grass after a heat wave. The wet-grass water drains quickly, while water in the cup demonstrating a normal summer trickles down slowly but steadily, and the “after heat wave” cup looks nearly stagnant.
“Damp grass takes 9 seconds, moist grass (more like normal in summer) 52 seconds, parched grass (most this year) looked likely to take at least 15 minutes … but I got bored,” Thompson wrote.
Credit: Dr Rob Thompson/University of Reading via Storyful

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[SpaceTimeSynth]

This tracks. The experiment could be a little more involved but I agree with this. My credibility - having lived in Texas and witnessing with my eyeballs flash floods more often and more sudden after long droughts and less often and less intense when there was no drought.

[MrBandorr]

Anyone else look this up because of Cox and Crendor?

[zoopers]

So many stupid people in these comments.

I keep tarantulas. Some of them need to be in more arid enclosures. Some need their soil more wet. Recently I went on holiday for two weeks and couldn't spray down their soil regularly. When I got back, some of their enclosures had completely dried out. It was incredibly difficult to moisten the soil again, because the dried out soil simply would not soak up water. It would simply sit on top and take ages to soak in. Do you know which enclosures didn't have that problem? The more humid enclosures where the soil had not completely dried out yet.

[NjoyMoney]

It is absorbing water, you can see it from the bubbles coming out, the water is displacing air.

[jackielighten]

This is clearly because lots of wet grass means the seal around the cup is poor allowing o2 to displace the water. A tiny amount of dry grass means there is a good sea and so water isn't displaced. Put a hole in the top of the cup and water rapidly enters on fry grass. Why are people so gullible

[miasmicdreamer]

Dick move making me leave my web browser for a demonstration. 10/10 thanks

[spookje]

Too bad this is the wrong way to show the correct message.

[tfitz]

This is terrible. Sure, add a cup of water on further compacted grass. You want a real test, put the cup on the bare soil

[rogerholland]

I don't think this is a valid experiment. It is simply measuring the effect of a vacuum inside the cup. Cut a hole in the bottom of the cup, then invert it. You will probably get much different results.

[alberth]

expérience biaisée, il y a de l'air qui rentre sinon le verre ne se viderait pas, ce qui prouve simplement que l'herbe soulève le verre et donc l'eau se déverse en dehors du verre. On apprend ça au collège il me semble, du moins dans les années 90.

[chippyjohn]

We don't need to worry about a 40 degree summer as much as we need to worry about these people who are considered intelligent because they bought a degree.