The year marked the most severe wildfire season across the West to date, with California logging five of its six biggest wildfires in state history. It was also the Atlantic’s busiest hurricane season on record, with 12 landfalling named storms in the United States, while swarms of tornadoes ravaged the South.
The most expensive disasters stemmed from severe thunderstorms and tornadoes. Hurricanes and tropical storms were close contenders, plaguing the Gulf Coast with relentless back-to-back strikes.
The disasters stand against the backdrop of a warming climate, with annual average temperatures in the Lower 48 states running 2.4 degrees above the 20th-century baseline. Globally, 2020 tied 2016 for the hottest year on record, according to data from the Copernicus Climate Change Service.
Climate change is tied to larger, more extreme fires, hurricanes that intensify more rapidly and other trends that lie behind an increase in disaster damages. Another factor is population growth, with more people and buildings in harm’s way.
“Weather events have always and will always occur,” Steve Bowen, head of catastrophe insight at Aon Insurance, wrote in an email. “But with climate change expected to increasingly affect the behavior of weather events, and if you tie that with more ‘stuff’ in harm’s way, then the expectation is that resultant loss totals will also increase in the future.”
While the number of individual billion-dollar disasters topped the charts, 2020 still lags behind 2005, 2012 and 2017 for overall costs. 2005 hosted a record hurricane season that included storms Rita, Wilma and Katrina, while storms such as Harvey, Irma and Maria raged in 2017. Hurricane Sandy slammed New Jersey and New York City in 2012.
Thunderstorms were the costliest hazard of 2020
Thirteen of 2020′s billion-dollar weather disasters resulted from outbreaks of severe thunderstorms and tornadoes, including several very costly hailstorms.
Nashville was hit by one of the year’s most devastating storms. Residents went to sleep the night of March 2 with the forecast calling for isolated strong thunderstorms and a very low tornado risk. Instead, a vicious EF3 twister plowed through the city after midnight, while an even stronger EF4 ravaged Cookeville, 80 miles to the east. Twenty-five people died in the largely unpredicted storms, which caused $2.5 billion in damage.
April was jam-packed with costly severe weather, including at least three major tornado outbreaks during the historic month. With 351 tornadoes, the month was the second-most active April for tornadoes on record, behind only the famous outbreaks of April 25-28, 2011. The most substantial outbreak occurred on Easter Sunday, April 12. At least 140 tornadoes touched down during the twister swarm, which cost $3.6 billion and was blamed for 35 deaths.
The year also brought the most expensive single thunderstorm in U.S. history — the Corn Belt derecho of Aug. 10.
A nondescript batch of severe thunderstorms blew up into a top-tier windstorm as it roared across Iowa during the early afternoon, lashing some communities like Cedar Rapids with winds of 120 to 140 mph. Unlike a tornado, this damage wasn’t localized — destructive to extreme winds plowed a path 770 miles long in 14 hours.
Much of the damage was agricultural; 10 million acres, or 43 percent of Iowa’s corn crop, was affected. Eleven billion dollars in damage resulted.
A pricey hurricane season
A week before the derecho raked Iowa, hurricane season kicked into full force along the Gulf and East coasts. First up was Isaias in early August, a low-end Category 1 hurricane that rode up the Eastern Seaboard as a tropical storm. Damaging winds from the Carolinas to Maine cut power to millions, while the storm generated 34 tornadoes in the Mid-Atlantic and flooding rains. It caused 16 deaths and nearly $5 billion in damage.
And that was just the beginning. August concluded with the most powerful hurricane to hit Louisiana in 150 years when Category 4 Hurricane Laura slammed Lake Charles with 150 mph winds. An “unsurvivable” storm surge narrowly missed the city. The storm incurred at least $19 billion in damage and claimed 42 lives. On Oct. 10, Category 2 Hurricane Delta hit virtually the exact same area, causing an additional $2.9 billion in damage and yanking off hundreds of tarps serving as temporary roofs after the passage of Laura.
According to Munich Re, an insurance company, hurricane-related losses in the United States this year came to $43 billion. That’s about a fifth of the total loss from all natural disasters worldwide during 2020. Six of the world’s 10 priciest disasters of 2020 hit the United States.
Drought and fire
In the West, storms weren’t the problem. In fact, it was the opposite — prolonged drought, extreme heat and widespread, strong offshore wind events, linked in large part to human-caused climate change, contributed to a record wildfire season.
More than 10 million acres burned across the West, including California’s largest fire on record — the August Complex. It started as 37 individual blazes that merged into a massive fire that torched more than 1 million acres, becoming the state’s first “gigafire.” Some 10,500 structures were damaged or destroyed in California alone.
In Oregon, historic wildfires burned more than 2,000 buildings, while Colorado experienced an extreme fire season as well. The Centennial State’s three largest wildfires on record all took place during 2020. On the whole, wildfires caused $16.5 billion in destruction.
The fires were fueled by persistent hot and dry weather, with California experiencing a long, hot spring, summer and fall, with its warmest August and September on record.
Studies have shown that climate change is causing more extreme fire weather days, which feature exceptional heat and dryness, along with strong and often erratic winds. Global warming has already led to a large increase in the occurrence of huge wildfires in the West, indicating that the massive blazes this year, which fouled the air across a broad region, were no fluke.
In early September, Los Angeles set a record high of 122 degrees, while temperature records fell up and down the Golden State.
That same record heat contributed to a worsening drought that engulfed the West, causing $4.5 billion in mainly agricultural losses.
The record number of billion-dollar events caused 262 deaths during 2020. Bowen says action is needed to address the increased movement of people into at-risk areas.
“While there is heavy focus on the frequency and intensity of events, we need to be equally highlighting that people are moving at an accelerated rate into some of the most vulnerable areas for extreme weather,” wrote Bowen. “It is imperative that we improve awareness around people better preparing their home or business in the face of inevitable [hazards].”
That, Bowen says, starts with knowing one’s own vulnerability.
“We need to ensure that people understand the natural peril risk at their location.”
Andrew Freedman contributed to this report.