To important events in tornado forecasting occurred in 1957. On April 2nd, a tornado cut a 16 mile path across the City of Dallas. Video of this virtually transparent tornado was used to study airborne debris. This allowed researchers to estimate actual wind speeds in the tornado.
On June 20th, the air was muggy in Fargo, North Dakota was extremely muggy. A broad upper level trough was over the northern tier of states. A surface low was over Central North Dakota. A stationary front extended from the low eastward to just north of Fargo. This front would move back north as a warm front that Thursday afternoon. Dewpoints by 5 p.m. at Fargo were in the upper 60s as moisture pooled just to the south of the retreating warm front. This would be the fuel for severe thunderstorms.
Everything broke loose at 7:30. Two brief tornadoes occurred before a monster funnel roared down to the west of Fargo. The tornado moved very slowly, only about 19 mph. This gave travelers along US-10 west of Fargo to warn the town. As the Fargo tornado continued toward the city, warnings were broadcast on television and radio.
Instead of taking cover, many residents ran outside to photograph and film the twister. Assigned by the U.S. Weather Bureau to study the violent F5 twister, tornado researcher Ted Fujita knew the photographs were important. An appeal was sounded and over 150 still photographs and five home movies were turned in. Fujita painstakingly recreated the vantage point of every photographer and the detailed second by second analysis that he did was very revealing.
Fujita was able to dissect the life cycle of the supercell storm and the tornado it produced. He coined the terms wall cloud, the collar cloud and the tail cloud, terms that are at the center of the spotter lexicon today. The watershed study of the supercell showed that these formations were not random occurrences, but indications of processes that are ongoing in a severe thunderstorm and therefore important visual clues to what the storm is going to do.
Unfortunately, ten people died in the devastating storm that destroyed 1,300 homes as it ground across the northern part of Fargo.
