Fire, Now after the Flood? How Some Types of Climate-Related Disasters Increase the Vulnerability of Others

For several weeks in July, when about five floods destroyed the city of Ruidoso, New Mexico, the causes were not as obvious as many people might think. Because although the rain was heavy at that time, it was not unusual especially for July, which is the beginning of the southwest summer monsoon that usually passes through September.

What made these rains different—and devastating—is that they followed the South Fork and Salt wildfires, which burned through the same area in June, burning trees and other vegetation that would have they helped reduce floodwaters and left burning scars—scorched earth that cannot be absorbed. rain, causing even stronger flows.

This is an example of how one disaster can increase the risk of others, an effect known as catastrophic disasters. The Ruidoso fires and floods also highlight the need to understand how disaster risks are related and why it is important to address those risks as quickly as possible, especially when the U.S. it still has high billion dollar crises at a time.

To help advance that understanding, The Pew Charitable Trusts identified four types of related disasters—extreme heat, drought, wildfires, and floods—to determine how much increased risk to one person could cause. how the danger of another, and what can be done to end the disaster. circuit.

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Excessive Heat

The summer of 2023 was the hottest on record—until the summer of 2024. In fact, August 2024 was the hottest month on earth since records began in 1880. These records are not just being driven. they are extreme heat waves in few places, but rather high temperatures. across all 50 states.

The trend has consequences: Heat-related illnesses will drive nearly 120,000 emergency visits across the US by 2023. And extreme heat increases the risk of drought by raising what scientists what they call saturation vapor pressure, or the amount of water vapor the air contains. I held. In short, warm air can capture and hold more water, which means increased evaporation rates and drier conditions on Earth.

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Drought

Over time, increased vapor pressure can lead to a so-called vapor pressure deficit—a measure of how dry the air is near the earth’s surface. The lack of vapor pressure causes the plants to accelerate the rate at which moisture is drawn from the roots, which can cause the plants to eventually wither and die, increasing the severity of drought.

In June and July—especially before the remnants of Hurricane Beryl brought much-needed rain to the South and Midwest—much of the United States faced drought. And drought can be costly. For example, last year’s drought conditions across South and Central America led to an estimated $14.5 billion in economic losses, ranking as one of the costliest disasters. by 2023. Drought can also increase the risk of…

Patrick T. Fallon

Wildfires

Drought increases the risk of wildfires because vegetation burns hotter as it dries. And when extreme heat and drought combine, according to the National Oceanic and Atmospheric Administration (NOAA), the effects can be devastating—including reduced runoff, dry soil, tree dieback, and “extreme fires that spread faster, burn more intensely. , and it costs a lot of money to suppress them.”

Wildfires in the U.S. are increasing in intensity due to three major factors: the growth of dense fuels, or flammable vegetation that increases the risk and intensity of wildfires; increased development in wildfire-prone areas; and an increase in the vapor pressure deficit. Wildfires caused significant economic and human losses in 2023, from Maui to the Great Smoky Mountains, with more than 55,000 fires burning 2.6 million acres across the US.

And the cost to the American taxpayer is growing rapidly, with the Congressional Budget Office reporting that federal spending on fire suppression has more than tripled since the 1980s, although adjusted for depreciation. Since 2000, wildfires have burned an annual average of 7 million acres across the US, more than double the annual average of acres burned in the 1990s. As mentioned above, this increases the risk of the fourth type of disaster.

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Floods

As shown in the Ruidoso disasters, the wildfires and the burning scars they left behind created a situation where any significant rainfall could cause flooding. As the National Weather Service (NWS) explains, “Rain that would normally be absorbed will run off quickly after a wildfire, as burned soil can hold water like a paved road. As a result, it takes very little rain to cause a severe flood.” The NWS also says, “If you can look up from where you are and see a burned area, you are in danger.”

According to a Pew analysis of NOAA data, in the two decades since 2000, at least one flood occurred somewhere in the US on eight out of every 10 days, on average. And these events are not limited to coastal areas. In fact, river and flash floods, especially in inland and mountainous areas, cause more damage each year than hurricanes and other coastal storms.

All levels of government have a lot of work to do to reduce the effects of the increasing disasters. A recent study from the National Academies of Sciences, Engineering, and Medicine finds that while many communities have traditional accident plans, they are less likely to Plan multiple events in sequence.

Comprehensive resilience strategies must use forward-looking data and science to identify the causes of risk and provide measures to reduce the likelihood of severe disasters and their adverse effects on people and nature.

The tragic events in Ruidoso show how important it is for national, state and local governments to take immediate action to understand their vulnerability to climate-related disasters and implement strategies. comprehensive resilience strategy, plan and projects.

Mathew Sanders leads federal-level efforts to plan and build resilience to current and future climate-related disasters for Pew’s US conservation project.