The National Oceanic and Atmospheric Administration announced Monday that at least 20 individual billion-dollar disasters occurred in the United States in 2021, the second-most on record. From tornadoes to floods, fires and hurricanes, the year featured a number of catastrophes, many of which were made more severe by human-induced climate change.
Racking up a price tag of more than $145 billion, the disasters of 2021 combined into the third-costliest year on record dating to 1980, according to NOAA. At least 688 people were killed. The only costlier years were 2005, which featured Hurricane Katrina, and 2017, during which hurricanes Harvey, Irma and Maria made landfall.
The 2021 billion-dollar disasters include exceptional heat and drought in the western states, a rash of wildfires, a punishing cold snap in Texas, four tropical storms and hurricanes, and eight severe thunderstorm/tornado events.
The exceptional year for these costly disasters concluded with two record-setting tornado outbreaks in the Southern and Central United States fueled by the nation’s warmest December on record. The month was nearly seven degrees warmer than normal, with 10 states — mostly in the Southern and Central United States — seeing their record-warmest December.
The record-warm December capped the fourth-warmest year on record for the country. The temperature averaged over the United States was 2.5 degrees above normal and fit into a long-term trend toward rising temperatures. All six of the warmest years on record in the United States have occurred since 2012.
How the record-warm December fueled unprecedented severe storms
The warmth in December came in several waves and was aided by record warm temperatures in the Gulf of Mexico. As just one example of how warm it was, Houston came in at 13 degrees above normal, crushing its previous record for warmest December by more than four degrees. It was even warmer than its previous record-warmest November. In several instances, temperature soared more than 30 degrees above normal and set state records.
Two of four record-setting pulses of warmth could be directly tied to rounds of destructive thunderstorms and tornadoes that were more prolific than anything witnessed in the spring.
More than 90 people died in a swarm of tornadoes on the night of Dec. 10 and 11 that included multiple long-track EF4s that pounded neighborhoods into rubble across Arkansas, Tennessee, Missouri and Kentucky. The devastating tornado that tracked through Mayfield, Ky., was on the ground for 166 miles, the longest-track twister on record in December and in the top 10 longest for any month. It was the deadliest December tornado outbreak ever recorded in the United States.
Just days later, another tornado and severe weather outbreak occurred, this time with a derecho, or violent squall line of destructive winds, on Dec. 15. It swept through the Corn Belt and north-central Plains, bringing the first December tornado to Minnesota on record and lashing Nebraska with widespread gusts topping 90 mph. More than 60 tornadoes touched down in the onslaught and a record number of hurricane-force wind gusts were clocked.
The disasters of 2021 at glance
Western drought and heat
The year began with continued severe drought in California, which at the time expanded over almost half the West. While dramatic improvement has since ensued due to prolific December snowfall, the drought would prove a slow-motion disaster that would wreak havoc on agriculture and severely impact the broader region’s economy. Numerous reservoirs dropped to record levels.
Excessive heat intensified the drought and, in many instances, blew past records. Death Valley soared to 130 degrees in July, considered by some the highest reliably measured temperature on record worldwide.
While difficult to put a price tag on, the unprecedented late June heat wave in the Pacific Northwest was blamed for hundreds of excess deaths. It sent temperatures skyrocketing to 108 degrees in Seattle and 116 in Portland, obliterating records. Scientists concluded that that event was made at least 150 times more likely due to human-caused climate change.
NOAA pegged the cost of the western drought and heat at $8.9 billion, 2021′s fourth-most expensive event.
The combination of heat and drought created tinderbox conditions for wildfires in the western states. California’s Dixie Fire, which consumed more than 960,000 acres, was the state’s second-largest on record. The smoke from the western fires spread across the entire country during the summer, degrading air quality even in the Mid-Atlantic and Northeast.
The year ended with the Marshall Fire near Boulder, Colo., which was the most destructive in state history. Occurring after an unusually warm and dry fall with hardly any snow, it damaged or destroyed more than 1,000 homes and businesses.
The fires — as a group — caused $10.6 billion in damages, the third-most costly disaster of 2021.
Floods in California and Louisiana
Interspersed in the pervasive aridity in the West were a number of atmospheric river events, including a fire hose of moisture that swept through Central California from Jan. 24 to 29.
“Rainfall totals exceeded 15 inches in Monterey and San Luis Obispo counties,” wrote NOAA, which triggered flash flooding and mudslides, including on burn scars left by wildfires between 2018 and 2020. Highway 1 south of Big Sur was washed out by the water, while several feet of snow fell in the Sierra Nevada. Extensive power outages also occurred. That event costs $1.2 billion, NOAA said.
A more subtle and localized flood disaster struck Louisiana in mid-May, costing $1.4 billion. It forced at least 250 water rescues as upward of 15 inches of rain fell. Hardest-hit were Baton Rouge and Lake Charles, the latter of which was continuing to deal with the aftermath of Category 4 Hurricane Laura and Category 2 Delta, which hit back-to-back during the late summer and fall of 2020.
A Texas-size cold wave
A piece of the polar vortex broke away from the North Pole in mid-February, leading to a once-in-a-generation cold event in Texas that knocked out power to 10 million people. Residents suffered through the coldest air mass to visit since 1989, with temperatures some 40 degrees below normal. Houston dipped to 13 degrees, Dallas to minus-2 and Oklahoma City to minus-14. Galveston even saw thundersnow, with snow recorded as far south as Brownsville and the Mexican border. With a damage price tag of $24 billion, it was the year’s second-most-expensive weather event.
Tropical trouble, headlined by Ida
The 2021 Atlantic hurricane season brought 21 named storms, exhausting the list of available storm names for the only the third time on record. Hurricane Ida was, by far, the worst of that group.
Ida brought both a flood and severe thunderstorm disaster to the Northeast, and a wind and storm surge disaster to southeast Louisiana. Gusts up to 172 mph were recorded near the Mississippi River Delta, the Category 4 storm whizzing ashore with 150 mph sustained winds near Grand Isle on Aug. 29. According to NOAA, every home in Grand Isle suffered damage and at least 40 percent were destroyed.
Ida went on to drop a slew of higher-end significant tornadoes across the Northeast, including an EF3 in Mullica Hill, N.J. Heavy rain was falling along the Interstate 95 corridor at the same time Midwestern-style twisters were carving through towns. A staggering 3.15 inches of rain came down in an hour’s time in New York’s Central Park, with 3.24 inches falling in an hour at Newark International Airport; both set one-hour records. Newark wound up with 8.41 inches on Sept. 1 alone, the city’s heaviest calendar-day total dating to at least 1931. More than 40 people died in widespread floods Sept. 1, which also overwhelmed infrastructure and drainage capacity.
Ida was the year’s costliest event, with damages of $75 billion, ranking as the fifth-most expensive hurricane on record.
Hurricane Nicholas impacted coastal Texas about two weeks later with 75 mph winds. While the storm wasn’t overly intense, its slow-moving remnants deposited additional heavy rainfall on soils already saturated by what fell during Ida. Damage was estimated at $1 billion.
Tropical storms Elsa and Fred managed billion-dollar price tags too, although both were accrued over lengthy stretches as their remnants brought pockets of flooding, wind damage and tornadoes.
Multiple thunderstorm, hail and tornado outbreaks
2021 was a seemingly backyard year for severe weather; the month of December yielded more tornadoes than March or April, but the spring tornadoes were still destructive.
A tornado outbreak March 24-25 dropped several long-track, powerful tornadoes in Alabama, one of which impacted cities like Greensboro, Brent and Centreville and stayed on the ground for more than 80 miles. An EF3 tornado tore through the southern suburbs of Birmingham and even damaged the home of veteran Alabama meteorologist James Spann, who stepped off the air momentarily to call his wife. An EF4 tornado later that night blew threw Newnan, Ga., with debris falling as far north as Atlanta. It was the strongest tornado of the year until December.
Hail in Texas was also responsible for multiple billion-dollar disasters. One hailstorm west of Austin brought a billion dollars in damage April 12, and a trio of hailstorms lashed suburbs of San Antonio, Fort Worth and Oklahoma City on the night of April 27. A “gargantuan” hailstone recovered in Hondo, Tex., was measured at roughly 6.5 inches in diameter and later certified as a record in the Lone Star State.
Another round of severe weather brought 111 confirmed tornadoes to the Mississippi Valley and the Southeast between May 2 and 4, with wind and hail too that, all together, culminated in a billion-dollar disaster.
Disaster toll increased by climate change and population and infrastructure growth
The majority of disasters in 2021 shared something in common: They were the result of natural variability, or randomness, but made worse by the effects of climate change and societal/socioeconomic trends.
Climate change makes heat waves, droughts, fires, hurricanes and precipitation more intense; at times, it may also make for more favorable tornado environments.
While climate change intensifies many weather events, the toll of disasters is also related to population growth and more infrastructure in harm’s way.
There’s no reason to expect a slowdown of disasters into 2022. Climate change isn’t going away, and the ongoing La Niña pattern favors both increased tornado and hurricane activity as long as it lasts.