The flooding occurring in Texas and Oklahoma (and throughout the plains) has been significant.  President Obama has made a disaster declaration for some of the hardest hit areas.  One ABC news report I read stated that parts of the region received 16 inches of rain in a week.

Besides the flash flooding, there have been hail, tornadoes, and high winds.   The drought Texas is experiencing has certainly been lessened; this is the wettest month on record for Texas and Oklahoma.  The National Weather Service is reporting that there has been enough rain in May to cover the entire State of Texas with 8 inches of rain.  That equates into 37 trillion gallons!  Incredible.

Sadly, the storms have claimed at least 43 lives, with others still missing.  Drones with heat sensing equipment are being deployed at some sites, looking for survivors.   Homes have been swept off their foundations.  Mandatory evacuations have been issued.   Dams and levees are being tested.

I am sure that many people are asking: how does this happen?  Besides the obvious, lots and lots of rain, what are some factors that can make floods worse?

FEMA TADD

The Harris County Regional Joint Information Center in Houston tweeted this.  Excellent post EMA officials!

Everyone lives downstream 

With the rains pounding an entire region, the precipitation that is falling to the ground must eventually head downstream.  All the excess water is causing the waterways to rapidly back up; the water has to go somewhere.  During a flood, the waters spread out instead of moving downstream.  Think of a massive traffic jam.  The water just cannot go any further until the traffic eases downstream.

Drought 

When an area receives little water, the ground becomes very hard.  Almost like concrete.  Instead of the rain soaking into the ground, the water is rapidly moving across the landscape to the nearest waterway…where it is finding a traffic jam. Additionally, the water table can vary across the landscape, which means only so much water can soak in.  I am not from that region, so I do not know if that is a factor.

Hard surfaces (impervious area)

In the urban areas, the sidewalks, rooftops, driveways, and more do not allow the water to soak into the ground either. Houston has a couple million people living there, while the Dallas-Fort Worth metropolitan area has over six million people…that is a lot of concrete and pavement.

Lakes and reservoirs

The bodies of water with dams are releasing as much water as possible from the overflows to relieve pressure and prevent it from failing.  The water also might overtop the dam, causing a failure.  In the low-lying areas below the dam, warnings in several areas for evacuation have been issued.  The extra water moving from the reservoirs far exceeds the normal rate.

Pumps on Dam

This image came from CNN and credits Brandon Wade with the pic. The caption states that this dam is in Padera Lake in Texas. As you can see, they are attempting to pump as much water as possible to keep pressure off the dam and prevent failure.

Various impacts

The impacts of this enormous flood event are tremendous.  People have lost their family members and beloved pets, while others have lost their home / business and belongings.

The economic impact will also be significant, with so many structures underwater or destroyed.  Utility companies, such as the electric company, probably have a lot of work ahead of them to repair the damage to their system.   Water companies will be working overtime to ensure that the drinking water is safe for consumption.

The environment also is impacted (think tsunami, flooding and Fukushima from a few years ago), with chemicals and other hazardous materials contaminating the water.  There is probably plenty of raw sewage out in those waters as well.

The flood finale

There is nothing that can currently be done to prevent flooding when an area receives 37 trillions gallons of precipitation.  Any place can experience a flood, provided enough rain falls and the conditions are right; floods are the #1 natural disaster in the United States for a reason.

Numerous factors, other than rain, help create a flood of this size.  With a continued push for creating comprehensive flood management programs in our communities, hopefully we can eventually reach a point where no lives are lost and no homes are destroyed.

If you live in Texas or Oklahoma and are experiencing this flood event, I hope that you and your family (which includes your pets) made it safely to higher ground.

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