[OKDXA] The Great Geomagnetic Storm of 1921

Wed May 13 16:33:23 EDT 2020

I don't remember the exact date, but in summer of 1967 I was stationed at Keesler AFB in Biloxi, MS.  I had bought my first boat and my parents were visiting.  We were out in the Gulf of Mexico at night and were treated to a marvelous display of aurora borealis while about 2 miles from shore.  I don't remember any particular hubbub about the causational storm.

I also remember the summer of 1958 when I still lived at home and was dating a young lady in Warren, PA (just south of the NY border) and we watched the display in my 1950 Ford convertible with the top down.  I just didn't think anything really special about it at the time.

73 de Mac, K2GKK/5
Since 30 Nov 1953
Oklahoma City, OK
USAF, Retired ('61-'81)
FAA, Retired ('94-'10)

________________________________
From: okdxa-bounces at mailman.qth.net <okdxa-bounces at mailman.qth.net> on behalf of Kim Elmore <cw_de_n5op at sbcglobal.net>
Sent: Wednesday, May 13, 2020 09:41
To: Oklahoma DX Association <okdxa at mailman.qth.net>
Subject: [OKDXA] The Great Geomagnetic Storm of 1921

This from a friend that, while not a ham, has a lot of interest in
astrophysics.

73,

Kim N5OP

*THE GREAT GEOMAGNETIC STORM OF MAY 1921: *99 years ago this week,
people around the world woke up to some unusual headlines.

"Telegraph Service Prostrated, Comet Not to Blame" — declared the Los
Angeles Times on May 15, 1921. "Electrical Disturbance is 'Worst Ever
Known'” — reported the Chicago Daily Tribune. "Sunspot credited with
Rail Tie-up" — deadpanned the New York Times.

<https://spaceweather.com/images2020/11may20/newspapers2.jpg>

They didn’t know it at the time, but the newspapers were covering the
biggest solar storm of the 20th Century. Nothing quite like it has
happened since.

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. For the next 3 days, CMEs rocked Earth’s magnetic field.
Scientists around the world were surprised when their magnetometers
suddenly went offscale, pens in strip chart recorders pegged uselessly
to the top of the paper.

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.
That fire, along with another one about the same time in a railroad
control tower near New York City's Grand Central Station, is why the
event is sometimes referred to as the "New York Railroad Superstorm."

What caused the fires? Electrical currents induced by geomagnetic
activity surged through telephone and telegraph lines, heating them to
the point of combustion. Strong currents disrupted telegraph systems in
Australia, Brazil, Denmark, France, Japan, New Zealand, Norway, Sweden,
the UK and USA. The Ottawa Journal reported that many long-distance
telephone lines in New Brunswick were burned out by the storm. On some
telegraph lines in the USA voltages spiked as high as 1000 V.

<https://spaceweather.com/images2020/11may20/sunspotar1842.jpg>
*Above:* Sunspot AR1842 on May 13, 1921. [more
<https://www.ann-geophys.net/33/109/2015/angeo-33-109-2015.pdf>]

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.

What would happen if such a storm occurred today?

Researchers have long grappled with that question–most recently in a
pair of in-depth papers published in the journal /Space Weather/: "The
Great Storm of May 1921: An Exemplar of a Dangerous Space Weather Event
<https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019SW002195>" by
Mike Hapgood (Rutherford Appleton Laboratory, UK) and "Intensity and
Impact of the New York Railroad Superstorm of May 1921
<https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019SW002250>"
by Jeffrey Love (US Geological Survey) and colleagues.

The summary, above, is largely a result of Hapgood’s work. He
painstakingly searched historical records including scientific journals,
newspaper clippings, and other reports to create a moment-by-moment
timeline of the storm. Such timelines are invaluable to emergency
planners, who can use them to prepare for future storms.

<https://spaceweather.com/images2020/11may20/aurorasightings_big.png>
*Above: *Aurora sightings in May 1921. The leftmost red circle marks
Apia, Samoa.

Jeffrey Love and colleagues also looked into the past and–jackpot!–they
found some old magnetic chart recordings that did *not go offscale* when
the May 1921 CMEs hit. Using the data, they calculated "/Dst/"
(disturbance storm time index), a measure of geomagnetic activity
favored by many space weather researchers.

"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.

This dry-sounding result upends conventional wisdom. Students of space
weather have long been taught that the Carrington Event
<https://www.swsc-journal.org/articles/swsc/pdf/2013/01/swsc130015.pdf>
(-/Dst/ = 900 nT) was the strongest solar storm in recorded history. Now
we know that the May 1921 storm was about equally intense.

If the May 1921 storm hit today, "I’d expect it to lead to most, if not
all, of the impacts outlined in the 2013 Royal Academy of Engineering
report
<https://www.raeng.org.uk/publications/reports/space-weather-summary-report>
led by Paul Cannon," says Hapgood. "This could include regional power
outages, profound changes to satellite orbits, and loss of radio-based
technologies such as GPS. The disruption of GPS could significantly
impact logistics and emergency services."

It’s something to think about on the 99th anniversary of a 100-year storm….