Geomagnetic Superstorms More Common Than You Think. The 1921 Storm You DIdn't Hear About Was As Big As The 1859 Carrington Event.

It began on May 12, 1921 when giant sunspot AR1842, crossing the sun during the declining phase of Solar Cycle 15, began to flare. One explosion after another hurled coronal mass ejections (CMEs) directly toward Earth. ... pens in strip chart recorders pegged uselessly to the top of the paper....And then the fires began. Around 02:00 GMT on May 15th, a telegraph exchange in Sweden burst into flames. About an hour later, the same thing happened across the Atlantic in the village of Brewster, New York. Flames engulfed the switch-board at the Brewster station of the Central New England Railroad and quickly spread to destroy the whole building....  On some telegraph lines in the USA voltages spiked as high as 1000 V.
During the storm’s peak on May 15th, southern cities like Los Angeles and Atlanta felt like Fairbanks, with Northern Lights dancing overhead while telegraph lines crackled with geomagnetic currents. Auroras were seen in the USA as far south as Texas while, in the Pacific, red auroras were sighted from Samoa and Tonga and ships at sea crossing the equator.

They found some old magnetic chart recordings that did not go offscale when the May 1921 CMEs hit....The storm attained an estimated maximum −Dst on 15 May of 907 ± 132 nT, an intensity comparable to that of the Carrington Event of 1859,” they wrote in their paper.

The expanded story with newspaper clippings from the day are at Spaceweather.com 
Update:  I see they picked it up from WattsUpWithThat.