Scientific American reports that, according to new data, the “New York Railroad Storm” of 1921 may have surpassed the intensity of the famous Carrington Event of 1859. In his paper published in the journal Space Weather, Jeffrey Love of the US Geological Survey and his colleagues reexamined the intensity of the 1921 event in greater detail than previously.
Although different measures of intensity exist, geomagnetic storms are often rated on an index called disturbance storm time (Dst) — a way of gauging global magnetic activity by averaging out values for the strength of Earth’s magnetic field measured at multiple locations. Earth’s baseline Dst level is about -20 nanoteslas (nT), with a “superstorm” condition occurring when levels fall below -250 nT. Studies of the very limited magnetic data from the Carrington Event peg its intensity at anywhere from -850 to -1,050 nT. According to Love’s study, the 1921 storm came in at about -907 nT.
Peter Ward in his 2017 New York History Blog article “Strange Phenomena: The New York Railroad Storm” recounted that theatre-goers in New York City “marveled at the spectacle” of an iridescent cloud that was brighter than the moon. “On the roof of the Times Building, reporters, having discovered the telegraph lines to be curiously blocked, gathered to watch the aerial kaleidoscope,” he wrote.
As with the earlier Carrington Event, telegraph operators experienced wild fluctuations in the current on their circuits, while wireless propagation was enhanced. “The next day, papers reported that the Central New England railroad station (also home to the telegraph switchboard) had burned to the ground.” Railroad officials later blamed the fire on the aurora.
According to Ward’s article, the lights were visible in New York, California, and Nevada. Especially in rural areas, “the lights were said to be brighter, appear closer to the ground, and even move with a swishing sound.”
Railroad and telegraph service were restored the following week, although one Western Union transatlantic cable showed signs of damage. “Delays and damage lead to some referring to it as the New York Railroad Storm,” Ward wrote.
A dramatic description of the event on the SolarStorms.org website said, “At 7:04 AM on May 15, the entire signal and switching system of the New York Central Railroad below 125th Street was put out of operation, followed by a fire in the control tower at 57th Street and Park Avenue.”
The short article said a telegraph operator reported being driven away from his station by flames that enveloped his switchboard and set the building on fire. “In Sweden a telephone station was reported to have been ‘burned out,’ and the storm interfered with telephone, telegraph, and cable traffic over most of Europe,” the article said.