Floods in Many Forms: A Growing Climate Threat
Photo courtesy of the US Geological Survey
we are thick dangerous season (aka summer), that time of year when droughts, heat waves, wildfires, floods, and hurricanes are more likely. Not only; climate change makes these disasters more severe and more likely.
This year, we’ve seen flooding around the world, so to speak, in “many forms.” This is when different types of flooding caused by rainfall, river flooding, storm surge, tidal flooding and/or melting ice occur simultaneously or in rapid succession.
In Kentucky, for example, heavy rains in July led to flash floods on normally dry surfaces. Then the rain continued, and the creeks swelled and caused them to overflow. This brought further flooding, inundating towns, destroying roads and bridges, and affecting disaster response and recovery for longer than flash floods alone.
We certainly know that multiple disasters can happen consecutively or simultaneously.One normal It’s the hurricane that hits and cuts off power during a heatwave.according to a article According to the American Geophysical Union, the number of these compound events has been increasing, but there is still a lack of understanding of the processes involved. We’re used to thinking of these composite events as discrete types of disasters, but what about when different variations of the same disaster happen at the same time?
It’s no surprise that most floods are associated with heavy precipitation. But flooding isn’t a simple concept — it’s more than just rising water levels and flooding an area. Andrew Cruzkiewicz of International Institute for Climate and Society me and others, just co-authored a paper Many forms of flooding were studied in the journal Environmental Research Letters. Our paper highlights the fact that not only are there different forms of flooding, but their physical and socioeconomic impacts and effects on communities vary widely, especially when they affect each other.
The article pointed out that “flood” has various subtypes such as river floods, coastal floods and flash floods. Each of these subtypes requires different approaches to reduce risk, build resilience, and prepare for future events. Some flood subtypes are well known and their impacts are addressed through policies and emergency management procedures. But this doesn’t work for all subtypes, and it doesn’t work for all types of interactions.
Flood subtypes can interact not only with each other, but also with other types of disasters. This means that tying everything under a “flood” leads to all kinds of challenges, with implications for humanitarian response and economic sectors. The effects of multiple forms of flooding may interact in ways not previously considered, resulting in inadequate response and management. This is especially true when events strike the most vulnerable.
In the paper, we mentioned the 2018 Hurricane Florence, as communities on the North Carolina coast evacuated inland to avoid coastal flooding, they found themselves facing a composite of inland flooding from river flooding and extreme rainfall. The concept of multiple forms of flooding and related emergency preparedness can be useful in this situation.
To better understand and respond to the many forms of flooding, more research is needed on the risk, vulnerability, and exposure of each subtype in order to adequately prepare for government programs aimed at limiting risk and building resilience.
Risk management models must track and disclose the specific flood subtypes they address, which assumptions are included (such as flow rates and hydrological characteristics), and which assumptions are excluded (such as pre-existing mitigation measures). Furthermore, understanding how the various flood subtypes interact with each other at different geographic and temporal scales is critical for assessing potential cascading and indirect impacts.
As climate change prepares to make flooding more frequent, widespread, and destructive, communities must understand their risk, and local, state, and national government agencies have the data and science to understand the risk, as well as the policies to mitigate that risk, and all required public outreach capabilities.
Of course, reducing emissions that contribute to global warming in the first place is our worst bet for avoiding future climate-driven floods and other disasters. At the same time, understanding the science and impacts of multiple forms of flooding can inform policymakers and ensure the resources needed to help emergency managers plan and communicate risk.
Astrid Caldas is a senior climate scientist at the Union of Concerned Scientists.This is an adaptation her article on their website.
