Floods
Summary
TLDR : Flooding is a natural hazard that can occur anywhere and at any time. Floods usually happen when extreme precipitation falls in short periods of time, often leading to increased water levels in rivers and waterways or overflowing onto land. Floods can also be caused by coastal storm surges, rapid snowmelt, and infrastructure failure. Floods have the potential to cause immense damage to property, infrastructure, and even take lives. Furthermore, when considering flooding, we must also plan beyond structure damage and consider the impact to transportation and utilities.
Background
Flooding happens when water submerges an area that is usually dry. Floods can happen within a matter of minutes, called flash floods, or can happen slowly over days, or even weeks. Any area close to a body of water like a stream, river, lake, or ocean, is at risk to experience a flooding event. Floods are typically connected to natural events such as heavy storms. Flooding can also result from infrastructure failure — for example a dam that breaks. Additionally, as sea levels rise, many coastal areas experience “sunny day” flooding — a phenomenon where floods happen without any rain event. Unfortunately, when extreme storms and failing infrastructure combine they often produce dangerous, devastating, and deadly conditions. Knowing where floods are likely to occur is key for reducing the impacts of flooding on individuals, families, businesses, and communities. By understanding the risks associated with flooding for your location it helps to prepare for the next flood event and ensure effective response and recovery efforts.
FEMA Flood Zones
Traditionally society has identified areas prone to flooding as a flood zone. In the US, FEMA designates which areas are flood zones. Flood zones are characterized by the risk associated with a precipitation event. Each zone is determined based upon historical water and precipitation statistical data, soil characteristics, and topography. This data is useful for understanding where floods have been known to happen throughout the years; however, the datasets fall short when it comes to helping people understand and visualize areas that are transforming into flood zones in the next few years. However, FEMA flood maps do not predict how the flood zones may change or include more and different areas in the future. This means that flood zones do not incorporate the effects of climate change or major new developments (new neighborhoods, expanding roads, etc.).
Flood Types
Coastal floods occur when an elevation of ocean water causes an overflow of the shoreline. Coastal flooding can be caused by storm surges, tsunamis, or high tides. Coastal areas are especially vulnerable to flooding due to the proximity and elevation of the shoreline. Inland flooding occurs along rivers, streams, and lakes when there is an overflow of these bodies of water due to heavy rain or snow melt. Flash floods are sudden and typically short-lived events that cause intense amounts of damage in a very brief period of time due to their rapid buildup. Because flash floods happen so quickly they can be difficult to prepare for since they usually come with little warning. To protect yourself and your property from any type of flooding, you should stay informed about current weather conditions, stay away from low-lying areas, and make sure your home is properly insured. Taking these steps will help ensure that you are prepared for any type of flooding event.
Climate Change
Climate Change impacts flooding in several ways. As the atmosphere warms, it can hold more water vapor, which leads to more frequent and intense rainfall. This can cause rivers and streams to overflow their banks, leading to more flooding. Another way that climate change affects flooding is through rising sea levels. As global temperatures continue to rise, polar ice caps and glaciers are melting, causing sea levels to rise. This sea level rise increases the risk of coastal flooding and erosion. Climate change can also exacerbate flooding by affecting the severity and frequency of extreme weather events. For example, hurricanes and tropical storms are becoming more frequent and intense due to the warming of ocean waters, leading to more flooding in coastal regions.
When Climate Change data is combined with FEMA flood data it allows us to better understand where the risks for flooding are in an area. This information helps communities plan for the future and to understand what might happen if the “big one” hits. By incorporating Climate Change data into flood planning it allows communities to increase their overall resilience.
Resources:
FEMA Flood Maps: https://www.fema.gov/flood-maps
First Street Foundation: https://firststreet.org/risk-factor/flood-factor/
If you liked this article please follow me@ Ryan Kmetz