The United States is an enormous country, spanning mountains, deserts, forests, prairie, tundra, and more. This varied terrain is also home to many natural hazards spawned by air, water, fire, and forces beneath the Earth’s surface.
Some of these threats are dramatic; the United States and its territories have the greatest number of active volcanoes of any country except Indonesia, as well as the most tornadoes. Other hazards, like heat waves, are less flashy but can still kill you.
Different regions of the country face very different hazards. But which part of the United States is the most dangerous? It turns out there’s no simple answer, although the south does have a particularly generous share of hazards. Here’s how the country’s natural menaces differ by geography.
What kind of dangers are we talking about?
The weather and geology of the United States allow for many natural perils and disasters. Earthquakes, volcanoes, blizzards, tornados, intense storms, wildfires, landslides, avalanches, sinkholes, flooding, droughts, heat waves, and more are all on the table.
“The U.S. is blessed with a wide range of natural hazard events,” says David Applegate, acting deputy director of the United States Geological Survey. And most of these hazards have hotspots around the country.
Volcanic eruptions are more common in the western states. Most are located in Alaska, the Pacific Northwest and Hawaii. Earthquakes are likewise common on the west coast, but also happen in portions of the central and eastern United States. In fact, a series of large earthquakes ripped through the area surrounding New Madrid, Missouri in 1811 and 1812.
Wildfires are most plentiful in the west, while snowstorms dominate in the midwest and northeastern states, and hurricanes and tropical storms strike the eastern seaboard and along the Gulf of Mexico.
Severe storms are common from Texas up into Southern Minnesota. The notorious Tornado Alley is located in the south-central states, although tornadoes also frequently hit Florida. “We have these broad expanses over which…the conditions are ripe for forming major thunderstorm systems and with plenty of nice smooth terrain for those to be able to form tornadoes,” Applegate says.
Florida is also prime territory for sinkholes, which happen in areas where the underlying rock can be easily eroded. Avalanches are most common in mountainous states, but they can happen wherever there is a steep enough slope with snow.
Some hazards make an appearance in nearly every corner of the United States. “Flooding is a fairly ubiquitous hazard that’s found pretty much everywhere,” says Susan Cutter, director of the Hazards & Vulnerability and Research Institute at the University of South Carolina. Rivers and coastlines are especially prone to flooding, while arid regions face droughts. Landslides are widespread as well.
And many natural hazards aren’t isolated events. “There are a lot of cascading consequences,” Applegate says. On top of wind damage and storm surge along the coast, hurricanes can cause immense inland flooding. This happened last year after Hurricane Matthew dumped more than 17 inches of water on North Carolina. Droughts can lead to wildfires, which in turn strip slopes of plants that hold the soil in place, priming them for landslides.
What part of the United States is most disaster prone?
It depends on what you’re looking at. Cutter and her colleagues have examined the death and damage natural disasters have wrought across the United States since 1960.
When it comes to property damage and economic cost, they estimate that Florida has taken the greatest hit from natural hazards. A lot of this comes from hurricanes, Cutter says, but flooding and fires have contributed as well. California comes in second for dollar losses, thanks to a combination of earthquakes, flooding, storms, and fire. “California kind of has it all,” Cutter says. Louisiana has sustained the third-highest amount of damage.
The states that endure the most damage are not necessarily the ones that have the greatest losses of life. Texas has the most hazard-related deaths due to severe weather and flooding, Cutter says. Illinois has the second-highest number of deaths thanks to urban heat waves like the infamous Chicago heat wave of 1995, followed by California.
By Cutter and her colleagues’ estimate, Los Angeles County has sustained the highest amount of damage, while Cook County, Illinois (where Chicago is located) saw more deaths than any other American county. Hurricanes are the most expensive disaster, while severe weather has claimed the highest number of fatalities. In 2008, Cutter also examined how hazards vary around the United States, and found that the south and intermountain west were the regions most prone to deaths by natural hazards.
A separate analysis by the National Oceanic and Atmospheric Administration has focused on disasters that caused damage of $1 billion or more since 1980. So far, there have been 208 such weather and climate disasters. Among these catastrophes, hurricanes have been both the deadliest and most expensive. The southern-central and southeastern states have experienced more billion-dollar disasters than other regions.
What state is safest?
“There’s really no safe place from natural hazards,” Cutter says. “Every place has some kind of exposure.”
Areas typically spared from dramatic events like tornadoes are not necessarily disaster-free. Vermont is still recovering from the catastrophic flooding caused by Hurricane Irene. “Even though the tropical storms may have petered out by then, it doesn’t mean that they don’t still have a lot of moisture that can be dumped,” Applegate says.
Far inland, the upper midwest is not known for hurricanes or earthquakes. But states such as North Dakota are also regularly endangered by flooding. “They have a very flat landscape so when the rivers break through their banks, they flood over a very broad area,” Applegate says.
Still, the region is probably your best bet for disaster-free living. “If I had to pick one area that probably is the least risky, I’d go with eastern Montana,” Applegate says. “And I’m sure they could [still] come up with impacts in terms of extreme cold and potentially drought and prairie fires.”
It’s also important to keep in mind that risk isn’t all about geography. Some states experience certain hazards like earthquakes only rarely, which leaves them less prepared when they do happen. “The built environment hasn’t been constructed to withstand that shaking,” Applegate says.
It also depends on where people live; a lot of the most appealing real estate lies in hazardous terrain along the coast, on steep slopes, or near forests that are consumed by wildfire. And some people are more vulnerable than others. “There are certain characteristics that influence the level to which people can prepare for, respond to, and recover form disasters,” Cutter says. People who are poor, lack access to transportation, or live in crowded buildings are more acutely jeopardized by natural hazards.
What else should I be worrying about?
The United States has a few living natural hazards, too. Parasite infestations don’t differ too much by region, although many of these tiny creatures need water to transmit between hosts and thus prefer moist areas. “Wherever there is water, there’s parasites,” says Lisette Arellano, a parasite ecologist at the University of Colorado Boulder.
Some of the most prevalent parasites in the United States are single-celled creatures called giardia. Giardiasis is commonly spread when backpackers or campers drink untreated water. “People see these beautiful mountain streams and then they drink the water without filtering it and then they have explosive diarrhea for several weeks afterward,” Arellano says. Giardiasis is widespread and is the most frequently diagnosed intestinal parasite in the United States, but in this country it is almost never fatal.
Much rarer and more deadly is Naegleria fowleri, aka the brain-eating amoeba. This single-celled protozoan usually minds its own business, but occasionally infects people when they inhale water through the nose. “It can enter the brain and reproduce, causing severe and usually fatal brain damage,” John Hawdon, vice president of the American Society of Parasitologists and a researcher at the George Washington University in Washington, D.C., said in an email. Most of these infections have happened in southern states, when people swim or dive in warm freshwater like lakes, rivers, or hot springs. “The amoeba thrives in very warm or hot water, so it is more common in the south, but there have been cases in northern states as well in the summer,” Hawdon says.
The United States has a few insect nuisances, like head lice and bed bugs, which are found across the country. People in the United States can, rarely, pick up tapeworms, which are also found around the nation, Hawdon says. He estimates that the most debilitating parasites are probably ticks, which pass on pathogens for illnesses like Lyme disease. That ailment is heavily concentrated in the northeast and upper midwest.
“We are pretty lucky in the U.S. in that we don't have to worry about most of the really dangerous parasites in the world, like malaria or schistosomiasis or intestinal worms,” Hawdon says. “This is mostly because of our excellent sanitation systems and mosquito control.” People who do suffer from these parasites in the United States nearly always contracted them elsewhere, he says.
Ultimately, he says, you aren’t likely to pick up a serious parasite in the United States.
What about wild animals?
The country’s diverse landscapes also hold diverse wildlife. Some of these species can be deadly, including rattlesnakes, black widow spiders, and big predators like mountain lions and alligators. But, while wild animals do occasionally kill people in the United States, this does not happen very often. In Yellowstone National Park, bears killed eight people between 1872 and 2015—fewer people than died from drowning, burns, or suicide in the park.
A few years ago, scientists examined animal-related deaths nationwide and found that most are actually related to cattle or horses attacking farm workers. Among wild animals, wasps and other venomous critters claim the most lives. Nearly half of deaths from animal attacks happen in the south. But altogether, animals only kill about 200 people annually. You’re more likely to be killed by dangerous weather; the National Weather Service estimates that in 2016, there were about 450 weather-related fatalities.
What can we do about natural hazards?
Scientists are working on ways to get ready for natural hazards, like improving predictions so we have a few more minutes of warning when a tornado, flood, or earthquake is about to happen. “We are doing everything we can to improve our ability to rapidly respond to these events,” Applegate says. “We’re seeing the cost of disasters increasing and the biggest driver of that is simply more people... moving into harm’s way.”
Ideally, people would not live in high-risk areas like barrier islands or in floodplains. “But that’s not how the country was settled,” Cutter says. “Most of our major cities are along rivers because that was the primary transport mechanism back in the day.”
People will always dwell along rivers and in seismic zones and other risky areas. But there are strategies that communities and individuals can adopt to reduce the dangers posed by natural hazards. We can design buildings to withstand earthquakes or floods. We can learn from disasters like the tornado that hit Joplin, Missouri in 2011 to improve our warnings and response in the face of emergencies. And people can plan ahead for natural hazards wherever they live (ready.gov has tips on preparing for different emergencies).
How is this going to change in future?
In coming decades, climate change is going to alter the pattern of natural hazards in the United States. “Earthquakes won't change, volcanic eruptions won’t change, but all of the other non-geophysical-related hazards will change,” Cutter says.
There will be more damage from major hurricanes, tornadoes, droughts, and wildfires. Disease-causing parasites like the brain-eating amoeba or disease-carrying parasites like ticks could expand their range and carry their diseases with them, Hawdon says.
But change is already underway, and costly hazards in the United States are on the rise. Last year brought the country’s second highest number of billion-dollar disasters, including drought, wildfire, floods, severe storms, and Hurricane Matthew. These 15 disasters killed 138 people and caused a total of $46 billion of damage.
Even now, living in some flood-prone areas has become untenable. The United States is resettling its first climate refugees from Isle de Jean Charles, Louisiana.
Another long-term risk is seen in rare catastrophes. There’s a good chance that the Pacific Northwest will be hit by a monumental earthquake in the next 50 years. And Yellowstone National Park is home to a supervolcano that would cause a far-reaching calamity if it erupted, although it isn’t likely to happen anytime soon.
“To make our society resilient to natural hazards, we have to deal with the ones that come knocking on a regular basis, but then also address the less frequent ones that have the potential to be truly catastrophic,” Applegate says.