Each year, natural hazards such as wildfires, droughts, floods, and avalanches threaten lives, damage infrastructure, and disrupt ecosystems across the United States. In just the last three years (2022-2024), the U.S. faced 73 different “billion-dollar” natural disasters, which is already more than the total number of (inflation-adjusted) billion-dollar disasters recorded in the 1980s (33), 1990s (57), and 2000s (67). These recent events have caused over $150 billion per year in damages to infrastructure and agriculture, and more than 1,500 fatalities.

Though these hazards are "natural," climate change is affecting their intensity and frequency across the country. It’s also making them harder to predict. When natural hazards are harder to predict, they’re also harder to prepare for, which makes forward-thinking science and risk-management strategies critical for helping communities learn about, plan, and respond to natural hazard risks near their homes, workplaces, and favorite recreation spots. Unfortunately, no place is without some risk of being impacted by natural hazards and the potentially large losses they cause to people, infrastructure, and agriculture. Explore a map from the Federal Emergency Management Agency (FEMA) to see the expected risks and losses based on natural hazards in different counties. 

Across the United States, rising temperatures, more frequent droughts, and the spread of invasive species are driving longer and more intense fire seasons. While fire is a natural, even essential, part of many ecosystems, climate change is shifting when, where, and how fires burn – creating fire patterns beyond what landscapes and people are used to handling. The CASC network partners with local experts to develop the knowledge and tools needed to help land managers prepare for region-specific wildfire risks and to support post-fire recovery efforts. CASC projects examine how droughts change the flammability of fuel in forests, how invasive species contribute to the spread of fire, and how key vegetation like sagebrush, aspen, sequoias, and mixed-grass prairies respond to changing fire regimes. Scientists are developing forecasts of future wildfire risks, tools to help land managers plan reforestation and recovery strategies after fires occur, and tools to anticipate “megafire” risks – ultimately creating fire-resilient ecosystems and safer communities. 

Unlike acute hazards like wildfires or hurricanes, droughts can creep in slowly and grow worse over weeks, months, years, or even decades. Across the country, drought is becoming more frequent, longer lasting, and more intense with climate change, affecting everything from groundwater storage to river flow and crops, forests, and entire ecosystems. Since 2000, the western U.S. has experienced some of the driest conditions on record. The Southern and Midwestern Drought and Heatwave in 2023 was one of the costliest natural disasters, causing over $14.5 billion in damages and taking 247 human lives. As the climate warms, the risk of extreme drought grows, threatening people, ecosystems, and the water supply. CASC scientists work with land managers to stay ahead of these risks. They seek to better understand how drought interacts with other stressors like rising temperatures and invasive species, to develop forecasts of where future droughts are likely to occur, to assess how ecosystems and critical natural resources are affected, and to create tools that help communities plan for how to best manage scarce water resources.

As droughts become more frequent across the U.S., intense storms and extreme precipitation events are causing more frequent and severe floods. Billion-dollar floods have occurred 45 times since 1980 and cost an average of $4.5 billion per year.  CASC scientists and resource managers are exploring how climate change is altering flood risks across the country – investigating everything from extreme rainfall in the Midwest, floodplain forest health along the Upper Mississippi, hurricane storm surge risk on the Texas Gulf Coast, and how coastal development might affect flood vulnerability in communities in the Southeast. Many of these projects turn to nature-based solutions, where repairing natural systems – wetlands, forests, and floodplains – reduces the risks and damage associated with flooding.

Avalanches are sudden, fast-moving flows of snow, ice, and debris that drastically reshape landscapes. They can threaten lives, disrupt transportation routes, and damage infrastructure. According to the Colorado Department of Transportation, when an avalanche shuts down Interstate-70 – which provides access to many ski resorts through the highest elevation stretch of interstate in the country – the economic loss is approximately $1 million per hour. While avalanches are a natural part of snowy mountain ecosystems, increases in air temperature, precipitation, and rain-on-snow events are altering avalanche patterns and behaviors, making them more frequent in some areas and more destructive in others, and generally harder to predict. CASC scientists are working with local managers to better understanding complex avalanche dynamics so they can make better predictions that will protect communities, safeguard critical infrastructure, and help managers make decisions in mountain ecosystems. 

Media

Sources/Usage: Public Domain. View Media Details

Glacial outburst floods (GLOFs) occur when large volumes of water suddenly escape from glacier-dammed lakes – bodies of water held back by ice or moraines (accumulated rock and sediment). These natural dams can fail due to increasing water pressure, ice collapse, landslides, or even heavy rainfall, triggering sudden fast-moving floods that rush downstream through subglacial channels with little warning. Often this occurs in a manner of hours. GLOFs can cause severe damage to roads, bridges, wildlife habitat, agriculture, tourism, and local economies – and pose risks to human safety. As glaciers retreat with climate change, new glacial lakes are forming and existing ones are growing larger and more unstable, increasing the threat of these floods in mountainous regions. CASC researchers are studying whether GLOFs may become more common as glaciers thin and melt under a warming climate and are developing new tools to forecast these floods in real time.

Natural Hazards rarely occur in isolation. Most interact in complicated ways: For example, invasive species can increase wildfire risk, wildfires can cause dangerous debris flows, and drought can worsen flooding when heavy rains follow dry periods. CASC scientists work with partners to study how these hazards interact and to help communities prepare for other natural hazards such as tornados, hurricanes, earthquakes, landslides, and atmospheric rivers. Through this work, they develop science-based tools and strategies to increase public safety and reduce economic losses.