As the 2014 EF4 tornado, at left, tore into Pilger, a twin twister spawned by the storm ripped across the countryside in this screencap from another storm chaser’s video.
What to do for a tornado watch versus tornado warning.
With tornado season ramping up in Nebraska, forecasters will be happy if this year percolates along like past years: relatively quiet.
Nebraska has been on a downward trend with tornadoes for more than a decade, said Ken Dewey, professor emeritus of applied climatology from the University of Nebraska-Lincoln.
Last year, Nebraska had 21 tornadoes, less than half the annual average — 51 — of the past 30 years, based on National Weather Service statistics.
“It’s really odd. ... The difficulty with science is we see things, but we don’t always have the answer to ‘why,’” Dewey said. “It was notable that there was a really big lack of tornadoes last year.”
Also notable, he said, was the fact that most of the state’s tornadoes occurred in the central and western parts of the state, which meant Nebraska’s major urban centers were spared.
A number of those tornadoes have occurred in the area served by the Hastings office of the National Weather Service, where meteorologist Mike Moritz is in charge of doing the damage surveys that determine if a tornado occurred, its path and its intensity.
Moritz said there’s a lot of unknowns with tornadoes, so it’s hard to discern whether anything of significance is happening.
A couple of factors could be at play in the drop in tornadoes, he and Dewey said.
Last year turned dry as tornado season hit its stride, Moritz said. The Hastings area started to fall behind on rain in April and was short on rainfall all summer.
And the jet stream didn’t set up quite right in 2020 to bring powerful storms into Nebraska, Dewey said.
Several prior years were noticeably rainy, which typically means cooler than normal weather. So in those years, the weather could simply have been too cool to generate the energy needed for a high number of tornadoes.
And prior to that, there were additional fairly dry years, which meant the needed moisture wasn’t there, Dewey said.
For tornadoes to form, conditions have to be “just right.” They need heat, moisture and a trigger, like a frontal system moving through.
One aspect to the 2020 tornado year was normal, Dewey said: Numbers peaked in June, followed by July. Those are the two months when Nebraska typically has its greatest number of tornadoes, he said.
After several rounds of high years in the 1990s and early 2000s, the trend downward started about 2006, weather service statistics show.
There’s no way, though, to bank on this trend, Dewey said: “Trends are fine until they are not.”
And as any emergency manager would say: One tornado striking a city is all that’s needed to make a slow year a bad year.
“A trend does not account for the fact that there can be atmospheric surprises,” Dewey said. “This year could give us a big atmospheric surprise.”
10 unusual weather events in the Midlands through the years
March 23, 1913: Omaha Easter tornado
An estimated 103 people were killed and 350 injured in the Omaha area when the tornado struck with no warning on a warm Easter Sunday. About 750 of Omaha’s more than 2,000 damaged houses were destroyed. The tornado — now categorized by the National Weather Service as an F4 storm with 166- to 200-mph winds — was part of the most catastrophic outbreak of tornadoes in eastern Nebraska and western Iowa history. More photos.
Here, people stand at 2410 Lake St. after the tornado.
July 1936: Dust Bowl
Nebraskans experienced the worst of the Dust Bowl in July 1936. The state experienced scorching heat, with Omaha hitting 114 degrees. The city recorded 35 days that year with temperatures of 100 degrees or higher. Air conditioning was not yet common and people slept outdoors to catch a breeze.
Here, a dust storm approaches Naponee, Nebraska, in 1935. The large building is the First Congregational Church.
Jan. 2-3, 1949: Blizzard
One of the worst blizzards on record suffocated all but southeast Nebraska. The region’s economy teetered on the edge of collapse as ceaseless winds and fresh snow defied efforts to keep roads and rail lines clear. Livestock by the tens of thousands died of starvation and exposure. Whole towns rationed food, and some residents burned furniture for household fuel.
Here, Vincent McKeown stands beside his car in a 20-foot deep snow canyon made by plows on Highway 275 10 miles west of Norfolk, Nebraska.
April 1960: Flooding
Melting from a heavy winter snowfall led to widespread flooding across eastern Nebraska. Rivers were already swollen when rain, followed by up to 9 inches of snow, swept the area April 1.
Here, H.H. Lallman (foreground), 71, chats with Chris Martinsen, 77 and Johanna Keilstrup in Winslow, Nebraska during Elkhorn River flooding.
Jan. 10-11, 1975: Blizzard
The storm raged across eastern Nebraska and caused deaths in five states. Omaha had just an inch of snow on the ground at 6 a.m. Jan. 10, but by 9 a.m. the city had declared a snow emergency. At one point an estimated 10,000 vehicles were stuck, stalled or abandoned in Omaha. Winds reached 60 mph, creating drifts as high as 10 feet. More than a foot of snow fell. More photos.
Seen here are vehicles stalled on 72nd Street south of Dodge.
May 6, 1975: Omaha tornado
An F4 tornado with winds of more than 200 mph tore through a nine-mile-long section of Omaha, killing three people and injuring more than 100. Early detection, aided by storm spotters, helped prevent greater loss of life. The National Oceanic and Atmospheric Administration in 2013 ranked the damage as the eighth worst tornado in U.S. history at an inflation-adjusted cost of more than $1 billion. Read more.
Here, an aerial view of the Westgate area is seen on May 7, 1975.
Oct. 25-26, 1997: Early snowstorm
Heavy, wet snow fell on still-leafy trees across southeastern Nebraska, resulting in downed tees, limbs and power lines. Streets were blocked, and houses and cars were damaged. The storm killed an estimated 3 percent of the Omaha-area’s trees and damaged another 30 to 35 percent. More photos.
Seen here is a snow-covered street and crushed trees near Miller Park in Omaha on Oct. 26, 1997.
June 22, 2003: Supersized hailstone
Aric Brophy, left, of Aurora, Nebraska, raced outdoors to retrieve a hailstone and impress his kids. He came back with the then-largest hailstone on record for the U.S.: 7 inches across and 18.75 inches around.
Summer 2011: Missouri River flooding
Heavy snowmelt and record spring rains in the upper part of the Missouri River watershed overwhelmed levees and imperiled the six massive dams that control the Missouri’s flow. Flooding lasted four months and caused billions of dollars in damage.
U.S. Highway 136 is seen here running east of Brownville, Nebraska, over the Missouri River channel and into flooded Missouri farmland on July 15, 2011.
Aug. 4, 2016: Lake Manawa waterspout
A long and lanky waterspout formed over Lake Manawa about 5:30 p.m., mesmerizing the many people in the metro area who saw it. After waltzing on the lake for 10 minutes or so, it broke apart. A spectacular sight, the tornado was harmless, because it had anchored itself to the lake. Had it not occurred in a populated area, the waterspout’s existence would have gone unrecorded. That’s because it was a rare tornado that formed independent of a supercell thunderstorm. It was so weak and out of place that it didn’t show up on radar, nor did it leave a trail of damage. More photos.
Nancy Gaarder
Nancy Gaarder helps cover public safety and weather events as an editor on The World-Herald's breaking news desk. Follow her on Twitter @gaarder. Email: nancy.gaarder@owh.com
