Flooding is where water overflows onto dry land, common during heavy periods of rain, when snow melts too quickly, or when ocean waves come onto shore. Flash floods are a rapid overflow of water in a short period of time, whilst other flooding may be gradual and last longer periods of time, whether this is days, weeks, or even months. Texas & Houston flooding is especially common due to the flat and clay soil terrain, paired with the fact that Houston barely rises above sea level.
However, what separates flash floods in particular from regular flooding is how dangerously quick they develop and the power behind the water. Flash floods are a result of heavy rainfall, with both the ground and drainage systems unable to absorb or clear the water. Likewise, flash floods may also occur when water fills dry creeks, or streams, sometimes overflowing over banks, resulting in a rapid increase of water in a short period of time.
What locations are particularly prone to flooding?
Closely populated areas are generally of high risk of flash floods. This is because the number of buildings, highways, shops, and other structures reduce the absorption via the ground of the water. This increases the flash flood potential as the water cannot be drained as quickly.
However, areas located near rivers are especially at high risk of flooding. When rainfall increases, the rain banks are often compromised, with water overflowing over the banks and into populated areas such as cities or towns. Similarly, when leaves enter the rivers this can cause them to fill up much quicker, especially when leaves also block drainage areas in cities. This makes flooding more dangerous as there is nowhere for the water to go - it needs to be pumped manually to be cleared. For example, in 1993, an abundance of leaves built-up in the Mississippi river, resulting in disastrous flooding.
Furthermore, streams that run through cities and towns are often routed into underground storm drainage systems. However, during periods of heavy rain of flash flooding, these systems can become easily overwhelmed or clogged due to fallen debris e.g. trees, branches, or even litter. Consequently, if these systems are blocked, this compromises low spots such as underground parking garages, basements, and underpasses; these can become very dangerous, very quickly.
Moreover, rural areas with mountains or cities with steep hills produce rapid runoff, this causes streams to rise quickly. In more rural areas, where there are rocks and clayey soils, these do not allow much water to infiltrate into the ground. This too, can cause flash flooding as the water has nowhere to go, compromising rivers and embankments.
It’s not uncommon for thunderstorms to also produce heavy rainfall. In the event of a thunderstorm, it is advised not to camp near a river or creek. This is because these can fill rapidly, with the water level almost doubling in size. Camping can become dangerous with little to no notice, so be sure to check the weather forecast before pitching up, whilst also avoiding camping near rivers or creeks entirely for your own and others safety.
Other areas of risk of flooding
Other high-risk areas of flooding include mountain and urban areas from both pavements and rooftops - this encourages water runoff and thus the risk of flooding.
Similarly, deep snowpacks also increase runoff as a result of quickly melting snow. When heavy rainfalls onto a melting snowpack, this can produce flash flooding as the snow turns into water too quickly.
During winter, thick layers of ice often form over both streams and rivers due to the rapidly declining temperatures. Both melting snow on top of this ice, or warm rain may cause the ice to lift or break. Consequently, large chunks of ice may jam against large structures such as bridges. Water then rises quickly behind this jam, causing flash flooding.
In some cases, large chunks of ice can be pushed downstream and onto shore, sometimes into houses or other buildings. This is dangerous both initially and when it melts, building a large amount of water up in a small space.
If you live in areas particularly prone to flooding, whether Houston, Texas, in largely dense areas or near banks or rivers, flood insurance is a must.
Whilst many home insurance policies cover general damage, they often do not include water or flooding damage. Therefore, it’s essential to be prepared, protecting your home and your family’s livelihood.
Remember: flash flooding is possible within many different areas. It’s important to remain alert and vigilant, take necessary precautions, and always get to higher ground as quickly as possible. The majority of flood-related fatalities are from cars driving into flooded roadways, if the flooding has already started it’s best to wait it out.