The February 1872 Great Geomagnetic Storm

What happened

Often called the Chapman-Silverman storm, this remains one of the three most extreme geomagnetic storms in the observational record, alongside the 1859 Carrington Event and the 1921 New York Railroad Storm. Peer-reviewed reconstructions place its Dst as low as roughly -834 to -1900 nT. Aurora were credibly reported within about 20 degrees of the magnetic equator — at Bombay and Shanghai — and transatlantic telegraph cables recorded induced voltages of 1,000-2,000 volts, forcing operators on Valentia Island to fully disconnect their instruments to avoid burning them out.