IOWA DERECHO 2020

2020 took bad weather to new extremes

Iowa derecho one of many billion-dollar events

The roof is missing Aug. 17 from an apartment building at Cedar Terrace in Cedar Rapids, the result of the derecho for a
The roof is missing Aug. 17 from an apartment building at Cedar Terrace in Cedar Rapids, the result of the derecho for a week earlier. Some families living in the complex were left sleeping in tents outside. (Liz Martin/The Gazette)

As most of us are breathing a sigh of relief that 2020 is finally over, many meteorologists are doing the same thing.

The year featured devastating wildfires and hurricanes, tornadoes, derechos and flooding, and just about everything else the atmosphere has to offer.

Wildfires and hurricanes were relentless and especially punishing, setting records for the amount of real estate impacted in the Lower forty-eight, while killing dozens.

Supercharged by climate change, they signaled trouble for the future as the climate warms further.

A year filled with extreme weather meant a hefty price tag: Insurance firm Aon estimates that at least 25 billion-dollar weather disasters unfolded across the United States in 2020.

“The United States has endured one of its costliest years for weather disasters on record and is facing an economic toll that will exceed $100 billion,” said Steven Bowen, head of catastrophe insight at Aon, in an email.

Fire season

Fueled by record heat and parched vegetation, fanned by howling winds and, at times, sparked by lightning, the West was plagued by an onslaught of devastating wildfires that began in June and continued to December.

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The fires occurred in a region that is trending hotter, drier and more susceptible to large blazes due to climate change.

In California, which saw a record wildfire season, a study published in August showed the frequency of fall days with extreme fire-weather conditions more than doubled since the 1980s.

In early September, when fires exploded not only in California but also Oregon and Washington, Nick Nauslar, a meteorologist at the National Interagency Fire Center in Boise, Idaho, said the eruption surpassed anything in the modern record.

“Multiple fires made 20+ mile runs in 24-hours over the last few days in California, Oregon, and Washington,” he said in an email. “Most of these fires are making massive runs in timber and burning tens of thousands of acres and in some cases 100,000+ acres in one day. The shear amount of fire on the landscape is surreal, and no one I have talked to can remember anything like it.”

In mid-September, the smoke from these blazes led to hazardous levels of air pollution along the West Coast and covered almost all the Lower forty-eight.

The 2020 wildfire season in California was off the charts in terms of area burned: 4.2 million acres were torched in blazes in just the Golden State alone.

Colorado also experienced record wildfire activity last fall that was only finally quelled when snow arrived.

Hurricane season

Last year will be remembered for decades to come. It proved the busiest Atlantic hurricane season on record with 30 named storms, more than two and a half times the seasonal average.

Thirteen hurricanes and six major hurricanes punctuated unending meteorological assembly line. A record 12 named Atlantic storms made landfall in the Lower forty-eight, including five in Louisiana. Two of those landfalls, Laura and Delta, were within 15 miles of each other; both ravaged the Lake Charles area.

Ominously, 10 storms rapidly intensified, their peak winds strengthening by at least 35 mph in 24 hours, tying 1995 for the most in a single season. Studies have shown rapid intensification becoming more likely as ocean waters warm due to climate change.

Tropical systems caused $38 billion in damages across the Lower forty-eight.

Storms and tornadoes

While hurricanes and wildfires were unforgiving, thunderstorms and tornadoes were the most expensive disasters in the Lower forty-eight in 2020.

Fourteen of the 25 billon-dollar weather disasters in 2020, headlined by the Iowa derecho in August and the Nashville tornado in March, were from thunderstorms.

“Perhaps to the surprise of many people, the biggest driver of losses in 2020 came from severe convective storms,” said Aon’s Bowen.

On Aug. 10, a cluster of run-of-the-mill thunderstorms in eastern Nebraska defied forecasts, exploding into a squall line of extremely destructive straight-line winds. The derecho blasted through Iowa with 140 mph wind gusts, buffeting 43 percent of the state’s corn crop and wreaking wide havoc.

Cedar Rapids was hit particularly hard, with numerous homes and businesses destroyed and only a fraction of trees left standing.

Damage rivaled that of an EF2 or EF3 tornado, but in a swath some 75 miles wide. Power outages lasted for weeks.

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The storms barreled east into Chicago with embedded tornadoes and winds estimated near 80 mph. In the derecho’s wake lay $7.5 billion in damage, making it the single costliest thunderstorm in U.S. history.

The Iowa derecho was just one of several such destructive storm complexes to rake across portions of the Lower forty-eight. A derecho slammed Philadelphia and southeast New Jersey in early June. Another derecho blasted a zone from Utah to Nebraska, including Denver, a few days later.

At least two dozen people died following a pair of surprise tornadoes that carved through Middle Tennessee overnight March 2 into March 3, striking the downtown Nashville area before cutting a strip through the landscape to the east over the next 50 miles.

Winter storms

The year began with a rather tame winter as a stable polar vortex kept blasts of frigid air bottled up that might otherwise trigger major snowstorms in the Lower forty-eight states.

But the winter of 2020-21 started with a blast as a blockbuster charged up the Mid-Atlantic and Northeast coasts.

A remarkable wave of low pressure drifting south of New England on Dec. 16 and 17 led to one of the most prolific Northeast snowstorms in recorded history.

A dumping of 35 to 45 inches of snow in 24 hours’ time occurred in a 350 mile band stretching from northern Pennsylvania and New York state through Vermont and New Hampshire and into western Maine.

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