Three massive hurricanes, severe storms and wildfires across the U.S. caused more than $306 billion in damage last year, making 2017 the most expensive year for climate disasters on record.

According to data released by the National Centers for Environmental Information (NCEI), which tracks the nation’s major weather and climate events, there were 16 “billion dollar” disasters in the United States in 2017, tying the record set in 2011 for most billion dollar disasters in a single year.

The total cost of each disaster includes insured and uninsured losses, including physical damages to buildings and infrastructure, along with factors like costs for businesses and damages to crops. Sources of data include federal and state agencies, the U.S. Army corps and the Insurance Services Office.  

What the study doesn’t account for, says study author Adam Smith, a scientist with the National Oceanic and Atmospheric Administration (NOAA), are health care-related expenses and the costs associated with loss of life. Smith told the PBS NewsHour over email that because of this omission, the study’s “estimates should be considered conservative with respect to what is truly lost.”

Smith also said that the data could change as recovery relief moves forward in harder hit areas. Costs in California in particular may increase slightly in the coming weeks as more information emerges.  

Why was 2017 such a bad year for disasters?

Michael Mann, distinguished professor of atmospheric science and director of the Penn State Earth System Science Center, said there is no doubt the sharp increase in weather disasters is an effect of human-caused climate change.

“The impacts of climate change now are no longer subtle,” he said. “We see them play out and in real time in the headlines, on our television screens.”

Many experts agree that although climate change is a factor in the formation and severity of these events, many other factors also contribute to extreme weather events, including urbanization and natural weather patterns. (Smithsonian Magazine dives into what we can and can’t attribute to climate change here). Smith said his study is not meant to tease out event attribution, and that for many of last year’s weather events, it will take months for scientists to determine which variables are linked to certain parts of climate change.

But Mann thinks that expensive disasters are catching the attention of big businesses who can’t afford to ignore an issue that could increase their costs in a big way. He said studies have found that choosing not to act on climate change is becoming more expensive than introducing policies or changes to fight it.

“They’re seeing their bottom line impacted, industry is paying the price,” he said. “The severe cost of extreme weather that disrupts supply chains, it creates havoc for markets.” Here is a look at all 16 record-setting disasters and why the damage was so expensive.

The Southern Freeze: $1 Billion
When: March 14 to 16, 2017
Deaths: 0
The damage: Though freezes in the south around this time aren’t uncommon, unusually warm temperatures caused crops to bloom weeks early, severely damaging farmers’ bottom lines. The Washington Post called it a “massacre” for fruit crops, with South Carolina and Georgia feeling the brunt  of the damage, with record temperatures in the 20s.

Southern Tornado Outbreaks and Western Storms: $1.1 Billion
When: Jan. 20 to 22, 2017
Deaths: 24
The damage: Southern states were pummeled by 79 confirmed tornadoes in January, sending strong winds as far west as San Diego. It was one of the largest tornado outbreaks for any winter month, outpacing a previous record set in the 1950s.

Midwest Severe Weather: $1.4 Billion
When: June 27-29, 2017
Deaths: 0
The damage: Nebraska, Illinois and Iowa saw hail, wind and tornadoes in June, with more than a dozen tornadoes touching down in parts of Iowa.

California Flooding: $1.5 Billion
When: Feb. 8 to 22, 2017
Deaths: 5
The damage: Heavy rainfall—and the subsequent high water, fallen trees, avalanches mudslides and sinkholes—caused severe property damage in Northern and Central California from. Damage to the Oroville Dam spillway forced 188,000 residents downstream to evacuate. And overflow from the Coyote Creek forced the evacuation of 14,000 residents from San Jose.

Midwest Severe Weather: $1.5 Billion
When: June 27 to 29, 2017
Deaths: 0
The damage: Severe hail, winds and tornadoes caused damage in 10 states across the midwest.

Missouri and Arkansas Flooding and Central Severe Weather: $1.7 Billion
When: April 25 to May 7, 2017
Deaths: 20
The damage:Storms dump 15 inches of rain in states across the Midwest, causing historic levels of flooding. Missouri, Arkansas and southern Illinois saw the worst damage, including from burst levees and flooded towns.

Central/Southeast Tornado Outbreak: $1.8 Billion
When: Feb. 28 to March 1, 2017
Deaths: 6
The damage: Seventy tornadoes ripped through central and southern states in what was the most severe weather outbreak ever to occur over a period of 48 hours.

Midwest Tornado Outbreak: $2.2 Billion
When: March 6 to 8, 2017
Deaths: 2
The damage: Eleven midwestern states were impacted by a tornado outbreak. Nearly one million people lost power in Michigan because of the accompanying high winds.  

Minnesota Hail Storm and Upper Midwest Severe Weather: $2.4 Billion
When: June 9 to 11, 2017
Deaths: 0
The damage: Minnesota and Wisconsin saw widespread damage from severe hail and high winds.

North Dakota, South Dakota and Montana Drought: $2.5 Billion
When: March 1 to Dec. 31, 2017
Deaths: 0
The damage: A “flash drought” characterized by extreme high temperatures and little rainfall hit North and South Dakota and Montana beginning in March. In addition to the increased wildfire risk, losses of cattle and agriculture spurred states to declare certain counties disaster areas.

South/Southeast Severe Weather: $2.7 Billion
When: March 6 to 28, 2017
Deaths: 0
The damage: Southwestern and southern states incurred widespread damage from large hail and high winds.

Colorado Hail Storm and Central Severe Weather: $3.4 Billion
When: May 8 to 11, 2017
Deaths: 0
The damage: Enormous, powerful hail pelted parts of Colorado and other southwestern states in May. Denver was hit with baseball-sized falling ice, which alone caused losses exceeding $2.2 billion.   

Western Wildfires, California Firestorm: $18 Billion
When: June 1 to Dec. 31, 2017
Deaths: 54
The damage: Wildfires burned more than 9.8 million acres of western U.S. territory in 2017, with cumulative costs triple that of last year’s fire season. California’s historic firestorm left 54 people dead and destroyed more than 15,000 homes and businesses. The combined destruction of all the California fires represents the most costly fire event on record and the most deadly since the 1930s.

Paul Steblein, wildland fire science coordinator for the U.S. Geological Survey, says these fires have also created challenges for future recovery. The increasing prevalence of invasive, quick-burning vegetation increases the likelihood that blazes will burn out of control. Additionally, the suppression of these large firestorms makes it difficult for natural, low-intensity fires—which help reset ecosystems that need to undergo periodic, controlled burns— to occur. This “ makes [recovery] increasingly difficult,” Steblein said.

Hurricane Irma: $50 Billion
When: Sept. 6 to 12, 2017
Deaths: 97
The damage: The Florida Keys, U.S. Virgin Islands and parts of the Caribbean were destroyed by Irma, which reached category 5 force by the time it reached St.John and St. Thomas. Mann says that the intensity is a result of rising ocean temperatures. With every one degree Fahrenheit increase in ocean temperatures, there’s a roughly 10 mile per hour increase in hurricane wind force, he said. “And we’ve warmed more than a degree Fahrenheit over the past century. That translates to more than 10 mile per hour increase in the strength of these very strong sort of category 4 category 5 storms.”

Hurricane Maria: $90 Billion
When: September 19 to 21, 2017
Deaths: 65

The damage: The costs of damage caused by Hurricane Maria are still being estimated as slow recovery continues on the island. Maria made landfall as a category 4 hurricane, decimating much of Puerto Rico’s agriculture, infrastructure and communication and transit systems. Mike Byrne, FEMA’s federal coordinating officer in Puerto Rico, told NewsHour that FEMA’s commitment to Puerto Rico has reached $5.9 billion. When asked what the biggest challenge to recovery is, he said he “wishes there was just one.”
Complex, rough terrain and slow-moving delivery of necessary building materials are among the largest challenges Byrne names. But he’s encouraged by the resilience of his fellow citizens and the progress of new technology, including microgrids that are bringing electricity to Puerto Rico’s most remote locations.

Hurricane Harvey: $125 Billion
When: Aug. 25 to 31, 2017
Deaths: 89
The damage: Houston saw unprecedented amounts of rainfall—up to 60 inches—by the time Hurricane Harvey had run its course. Damage exceeded $125 billion, second only to Hurricane Katrina’s level of damage. More than 30,000 people were displaced and 200,000 structures destroyed as a result of the flooding. According to John Nielsen-Gammon, regents professor at Texas A&M’s department of atmospheric sciences, Harvey was beyond the scope of what anyone could have imagined in terms of rainfall and severity. “Harvey was just so outside of the box it isn’t even something that we would expect to see again for quite some time,” he said.

This article is reprinted with permission from PBS NewsHour. It was first published on January 16, 2018.