A giant solar storm nearly triggered a nuclear war in 1967

The Bomb

Cold War history is rife with close calls that nearly led to nuclear holocaust.

In September 1983, for example, sunlight reflecting off a patch of clouds fooled a Soviet missile-warning system into detecting the launch of five US intercontinental ballistic missiles that never were. A wary colonel in a bunker ignored the alarm on a 50/50 hunch.

Two months later, US forces staged "Able Archer 83" — a massive nuclear-strike drill on the doorstep of the USSR. Soviet commanders panicked at the show of force and nearly bathed America in thermonuclear energy. Once again, an act of human doubt saved the planet.

Now scientists have one more hair-raising event to add to the books: The "Great Storm" of May 1967.

"The storm made its initial mark with a colossal solar radio burst causing radio interference ... and near-simultaneous disruptions of dayside radio communication," a group of atmospheric scientists and military weather service personnel wrote in a new study, published August 9 in the journal Space Weather.

Hours later, high frequency communications dropped out near US military installations in and near the Arctic — one of the closest places to station nuclear weapons and launch them at a Cold War-era Soviet Union.

"Such an intense, never-before-observed solar radio burst was interpreted as jamming," the study authors wrote. "Cold War military commanders viewed full scale jamming of surveillance sensors as a potential act of war."

A 'Great Storm'

Earth's magnetic field protects life on the planet by corralling the sun's high-energy particles toward the planet's polar regions.

If the sun happens to launch a cloud of solar particles directly toward Earth during a violent outburst, called a coronal mass ejection, it can trigger powerful geomagnetic storms.

This not only leads to beautiful auroras, but can also scramble wireless communications and disrupt radar systems.

The Bomb

While The Washington Post wrote up a story about the storm as "City Gets Rare Look at Northern Lights," top US military commanders sounded the alarms in secret.

The Air Weather Service (AWS) — a relatively new branch of the Air Force — had warned military leadership about the possibility of a solar storm, but US commanders believed the Soviet forces were jamming NORAD systems designed to detect threatening planes and missiles.

As the Strategic Air Command warmed up the engines of bombers and taxied toward the runway, the decision to go airborne may have been kicked all the way up to the "highest levels of government," possibly involving President Lyndon B. Johnson.

"Just in time, military space weather forecasters conveyed information about the solar storm's potential to disrupt radar and radio communications," according to a press release from the American Geophysical Union. "The planes remained on the ground and the U.S. avoided a potential nuclear weapon exchange with the Soviet Union."

And this all happened at the peak of nuclear armament — when a record 31,255 nuclear weapons were deployed around the world. (Today there are roughly 7,200 nuclear armaments at hand.)

"Had it not been for the fact that we had invested very early on in solar and geomagnetic storm observations and forecasting, the impact [of the storm] likely would have been much greater," study leader and UCAR atmospheric scientist Delores Knipp said in the release.

After the near miss, the researchers say the military learned to listen to its space weather forecasters, improve its abilities to see another looming "Great Storm," and avert the first and perhaps final global nuclear exchange.

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