Un-Tornado Alley? This spot has gone 21 years since its last Tornado Warning
Tornado Warnings are blaring across the Plains and Midwest this week, but head west of the Rockies, and you’ll find for some spots, it’s been more than a decade – or even decades since they've last had a Tornado Warning.
Where is 'Un-Tornado Alley'? One spot hasn't had a Tornado Warning in 21 years
While the blaring alerts of Tornado Warnings are a rite of spring in America's heartland, there is one area that hasn't had an official Tornado Warning in over 21 years.
EUREKA, Calif. – For those who live in Tornado Alley, hearing the blare of urgent Tornado Warnings could be a weekly occurrence in the severe weather season, if not even more frequent.
But there’s one place in America where it’s been a blissful 21 years of Tornado Warning-free worries.
As of Tuesday, there are large swaths of the Plains, South and mid-Atlantic that have gone less than a week or two since their last Tornado Warning, according to data compiled by Iowa State University. And with a severe weather system sweeping across the Plains and Midwest this week, many of those spots are already resetting to zero.
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For almost everywhere else east of the Rockies, save for the northern Great Lakes and northern Maine, it’s been less than a year.
Yet head west of the Rockies, and you’ll find that for some spots, it’s been more than a decade – or even decades.
It’s been 2.5 years since one was issued around Seattle. It’s been a four-year wait for Phoenix, nearly five years in Boise, Idaho, and over 12 years in Salt Lake City.
But no place has gone longer in the contiguous U.S. than the northwestern California coast. The National Weather Service office in Eureka last issued a Tornado Warning on Dec. 14, 2002, for a radar-indicated tornado/waterspout that was just off the coast heading toward Cape Mendocino. That would be over 21 years.
A chart showing number of days since each National Weather Service office last issued a Tornado Warning. (Data through April 16, 2024.)
(IEM / Iowa State University / FOX Weather)
It’s the only Tornado Warning issued by that office since reliable warning archive data is available back through 2001. Only Alaska’s offices, which haven’t issued any Tornado Warnings in that period, can claim a longer drought.
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While there are no tornado reports from that December day, there have been seven reported tornadoes in the area since 1983 – all of them in the winter. None were stronger than an EF-1 or F1 rating, and there were no injuries reported in any of them.
UNITED STATES - JULY 16: Scenic view of Pacific Ocean, Trinidad, California
(Carol M. Highsmith/Buyenlarge / Getty Images)
The consistently cool Pacific Ocean keeps severe weather at bay along the coast by thwarting the large temperature differences needed to generate strong thunderstorms.
What few tornadoes occur there typically come from cold, unstable air masses that sweep into the coastal areas from strong low-pressure systems and find just enough temperature difference and wind shear – the change in wind speed and/or direction with height – to generate weak rotation. For far Northern California, these storms usually form over the water and then blow ashore – six of the tornadoes in the past 40 years have all occurred along the immediate coastline.