Case Study · Solar Flare · 1967
May 23, 1967. A solar flare blacked out all three of America's Ballistic Missile Early Warning System radar sites simultaneously. NORAD commanders, believing the Soviets were jamming the radars ahead of a nuclear first strike, put nuclear-armed aircraft on ready-to-launch status. A space weather forecasting unit that barely existed intervened with the correct information in time. The event was classified for nearly 50 years. It was the closest solar weather came to triggering a nuclear war.
Cheyenne Mountain, Colorado · May 23, 1967
The year was 1967. The Cold War had been running hot for two decades. The Soviet Union and the United States maintained nuclear arsenals capable of destroying civilization, and both sides maintained continuous airborne patrols of nuclear-armed bombers — a literal doomsday clock that never stopped ticking. The three Ballistic Missile Early Warning System (BMEWS) radar stations — at Clear Air Force Station in Alaska, Thule Air Base in Greenland, and Fylingdales in the United Kingdom — were the first line of detection against incoming Soviet intercontinental ballistic missiles. They were NORAD's eyes. An attack on them — any deliberate interference — was explicitly considered an act of war.
On May 23, 1967, those three radar stations went dark simultaneously. The signals they had been broadcasting were disrupted, rendering them effectively useless. NORAD commanders, confronting the sudden blinding of their early warning network, had no immediate explanation. Their first interpretation: deliberate Soviet jamming. If the Soviets were jamming the US missile warning radars, it was the textbook prelude to a first strike. According to the peer-reviewed Space Weather journal study published in 2016 — co-authored with retired Air Force officers who were there — commanders put additional nuclear-capable aircraft on "ready to launch" status. The CBC News account documents the urgency: "NORAD feared this marked the prelude to an attack, so fighter pilots scrambled, and the world was just minutes away from a war between nuclear powers."
May 23, 1967
Date
3 Sites
BMEWS Radars Blacked Out
~50 years
Classified
Averted
By Space Weather Forecasters
What happened next is both technically specific and historically significant. The Air Force Weather Service had recently established a solar forecasting capability at NORAD's Cheyenne Mountain complex — a unit that had barely existed a few years earlier. The Arcfield Weather account documents: "A significant worldwide geomagnetic storm was forecast to occur within 36-48 hours, according to a bulletin from NORAD's Solar Forecast Center in Colorado Springs, Colorado on May 23." The forecasters had been tracking a large sunspot group that had been developing for weeks. They had records of extraordinary solar radio activity from observatories. Retired Colonel Arnold Snyder, who was at NORAD during the event, described his moment of recognition to Sky and Telescope: "I specifically recall responding with excitement, 'Yes, half the sun has blown away!' and then related the event details in a calmer, more quantitative way." The Air Force Weather Service solar forecasters extracted information from solar observations taken at the Air Force Cambridge Research Laboratory and convinced high-level decision makers at NORAD — and later the Strategic Air Command and the Pentagon — that the sun was jamming the radars, not the Soviet Union. The Space.com account of the study documents the turning point: "Those additional forces never launched." The planet survived what the Space Weather journal paper called "a near trip-wire in the tense political and military landscape of the time."
The Science
Think of radar as a system that emits radio pulses and listens for their reflections. To work, the radar needs to hear its own signal against a background of radio noise. A powerful solar flare produces intense radio emissions across a broad spectrum of frequencies — essentially flooding the radio environment with noise. When the sun's radio emissions are sufficiently intense at the frequencies used by radar systems, the radar cannot distinguish its own signal from the solar background. The BMEWS radars in 1967 used frequencies in the range the solar event was most strongly affecting. With the sun above the horizon at all three radar sites simultaneously, all three were struck by the same solar radio interference at the same time. The result looked exactly like deliberate, coordinated jamming — which is the worst-case military interpretation for simultaneously losing multiple early warning stations.
The 1967 event was classified because it revealed both the vulnerability of US missile defense systems to solar interference and the classified procedures by which nuclear launch decisions were made. The CBC account notes that the event "was classified, and she wasn't cleared to access it" — referring to Dr. Knipp, who had worked at NORAD for 22 years and only occasionally heard references to "an event" from the 1960s. The 2016 paper, co-authored with retired Air Force personnel, was the first public disclosure. The lesson it reveals is straightforward: solar weather is not just an infrastructure concern — it is a national security concern. A sufficiently powerful solar event can disrupt radar, GPS, communications, and the sensor systems that military and intelligence agencies depend on for situational awareness. In a context of international tension, disruptions that look like deliberate attacks can escalate toward the actions that a deliberate attack would trigger.
The most important detail in the 1967 story is the forecasting unit that stopped the military action. The CBC account quotes Dr. Knipp: "It was only maybe five years earlier that the program for training these officers had been conceived." The Space.com account of the study lead: "Had it not been for the fact that we had invested very early on in solar and geomagnetic storm observations and forecasting, the impact likely would have been much greater." The Strategic Air Command — which controlled nuclear-capable aircraft — did not have trained space weather forecasters on staff. NORAD was the only unit that did. "That changed very rapidly after this event," Knipp told CBC. The 1967 near-miss was the operational proof that space weather forecasting is not an academic or infrastructure topic — it is a function essential to military decision-making in a world where solar activity can mimic adversarial attacks on critical systems.
Timeline
01
Mid-May 1967: A large, complex sunspot group develops on the sun's surface. Solar forecasters at NORAD and Air Force Cambridge Research Laboratory track it. Extraordinary solar radio activity recorded. May 23 AM: NORAD Solar Forecast Center issues bulletin forecasting "significant worldwide geomagnetic storm within 36-48 hours." Solar forecasters have been watching this region. They know what is coming. The Strategic Air Command does not have trained solar forecasters. Neither does the Pentagon at this point.
02
May 23, morning: All three BMEWS sites — Clear (Alaska), Thule (Greenland), Fylingdales (UK) — simultaneously disrupted. Signals blocked. Radars blinded. NORAD commanders: no immediate explanation. The sites are in sunlight. Jamming all three simultaneously is a technically sophisticated military operation. The worst-case interpretation: Soviet prelude to nuclear first strike. Nuclear-capable aircraft put on "ready to launch" status. "Fighters scrambled." The world is, by one account, "just minutes away from a war between nuclear powers."
03
Simultaneously: NORAD's Air Weather Service solar forecasters, tracking the large sunspot group, recognize the signature. Col. Arnold Snyder: "Yes, half the sun has blown away!" Forecasters correlate: all three BMEWS sites in sunlight, receiving intense solar radio emissions. The "jamming" is waning as the flare intensity wanes — consistent with solar source, not deliberate jamming. Information conveyed up through NORAD to Strategic Air Command and Pentagon. Additional forces recalled. No launch. The forecasting unit that barely existed five years before the event prevented the event it was barely established to handle.
04
1967 onwards (classified until 2016): "That changed very rapidly after this event" — solar forecasting expanded to Strategic Air Command and Pentagon. Classified for ~50 years. 2016: Dr. Delores Knipp et al. publish in Space Weather journal with retired Air Force personnel for the first time publicly. "A near trip-wire in the tense political and military landscape of the time." Dr. Knipp: "This was a lesson learned in how important it is to be prepared." NOAA now maintains the Space Weather Prediction Center with 24/7 monitoring and military notification protocols.
Human Decisions
What worked
The Air Force Weather Service's solar forecasting capability at NORAD Cheyenne Mountain had been established approximately five years before the May 1967 event. Dr. Knipp's framing is precise: "It was only maybe five years earlier that the program for training these officers had been conceived." If that decision had been made five years later, the forecasters who recognized the solar signature in 1967 would not have been at NORAD. The information that prevented a nuclear exchange would not have been available. The program's existence was not the result of a specific threat assessment for this scenario — it was an investment in space weather monitoring capability that happened to be exactly what was needed. The lesson is not "the right people happened to be in the right place." It is "the investment made in advance created the capability that was needed."
Col. Snyder's recognition was rapid because he was already tracking the sunspot group. The Arcfield Weather account documents: "NORAD's Solar Forecast Center in Colorado Springs had already issued a bulletin forecasting a significant worldwide geomagnetic storm within 36-48 hours" — on the same day. The forecasters had the context to interpret what was happening because they had been monitoring the sun's active region for weeks. The correlation — all three BMEWS sites in sunlight simultaneously, radio emissions waning as the flare faded — was the diagnostic chain that identified the sun as the culprit. This is the argument for continuous space weather monitoring: the information that enables correct identification of a solar event requires a history of observation, not just a real-time reading.
The continuing relevance
The 1967 scenario is not historically unique. Solar weather regularly disrupts GPS (used for precision weapons guidance), communications (radar, satellite-based command and control), and surveillance systems. The difference between 1967 and today is that space weather forecasting is now a standard part of military operations — the Strategic Air Command failure that nearly launched a war is now a training case study for how not to respond to unexplained system disruptions. But the underlying vulnerability — that solar weather can produce effects that look like deliberate adversarial action — remains. A sufficiently large solar event in a period of international tension could still produce the same misinterpretation risk, particularly for systems operated by nations with less developed space weather awareness than the US and its allies.
The Space Weather Prediction Center at NOAA in Boulder, Colorado — which provides 24/7 monitoring, forecasting, and alerts for the civilian and military infrastructure that depends on accurate space weather data — is the institutional descendant of the barely-existing program that prevented a nuclear exchange in 1967. After the event, space weather forecasting was rapidly expanded to the Strategic Air Command and Pentagon. The current SWPC, which coordinates with NORAD and military agencies and provides public access to geomagnetic storm alerts at swpc.noaa.gov, is the 1967 lesson institutionalized. It is also the system that provided advance warning of the May 2024 G5 storm, enabling utilities to protect their grids.
The cascade lesson
The May 1967 solar storm is the most dramatic event in the history of solar weather preparedness — and the one that remained classified longest. The same physical phenomenon that collapsed Hydro-Québec's grid in 1989 and damaged South African transformers in 2003 also blacked out America's nuclear missile defense radar in 1967 and almost triggered a nuclear exchange. The difference between 1967 and catastrophe was a small group of military forecasters who had been trained, just barely, in time. Dr. Knipp's concluding statement from the 2016 paper — "This was a lesson learned in how important it is to be prepared" — is both an understatement and the most precise summary of what 1967 teaches. The preparedness investment that matters is made before the event it addresses. The space weather forecasting capability that exists today — NOAA's SWPC, military space weather operations, civilian utilities' GIC monitoring — is the accumulated consequence of the 1967 lesson being taken seriously for 60 years. Every year that it is maintained is a year that the 1967 scenario cannot repeat.
What You Can Do Now
The 1967 event's primary lesson is institutional: preparedness investments made in advance create the capabilities needed when the unexpected arrives. These five household-level actions apply that principle.
The 1967 radar blackout illustrates that solar storms don't just disrupt one system — they disrupt all systems that depend on radio frequencies the storm is affecting. A major geomagnetic storm can simultaneously disrupt GPS navigation, satellite internet, cellular networks, and HF radio communications. Planning for a period of several days with degraded or absent digital communications — having paper maps, local knowledge, a battery radio, and a plan that doesn't depend on GPS or internet — is the household level version of the military's hard lesson from 1967.
Solar storm communications guideThe forecasting unit that prevented the 1967 nuclear near-miss was the precursor to what is now NOAA's Space Weather Prediction Center (swpc.noaa.gov). Today's SWPC provides public access to the same geomagnetic storm watches and warnings that utilities, airlines, and military systems use to prepare for solar events. This is a genuinely useful early warning resource for households. Checking swpc.noaa.gov when you hear about solar activity, and knowing what G4 and G5 alerts mean and what to do when they're issued, is the civilian application of the military lesson the 1967 event produced.
Space weather monitoring guideThe 1967 event's core dynamic — unexpected system failure misinterpreted as deliberate attack — is not unique to NORAD. In periods of international tension, simultaneous infrastructure failures can be misinterpreted by governments, media, and populations as adversarial actions. A solar storm that disrupts GPS, internet, and power simultaneously could generate similar dynamics in a modern context. Understanding that solar weather can produce these effects — and knowing that NOAA/SWPC provides real-time information on whether a major solar event is occurring — is the public literacy version of the 1967 military lesson.
Solar storm awareness guideThe 1967 radar blackout lasted hours. A major modern geomagnetic storm could disrupt GPS, cellular, and internet systems for several days while the geomagnetic disturbance is active. A household 72-hour plan that works without electronic navigation, without electronic payment, without internet search, and without cellular communication is the practical response to the solar weather scenario the 1967 event represents. Paper maps of your local area, cash, and a portable radio are the three physical tools that close the most critical gaps.
72-hour preparedness guideThe barely-existing forecasting unit that prevented the 1967 nuclear near-miss was built by a small group of people five years before it was needed. Today's space weather forecasting infrastructure — NOAA SWPC, the DSCOVR satellite at L1, GOES space weather instruments — requires continuous funding and investment to maintain and improve. The advance warning that enabled utility operators to protect their grids during the 2024 G5 storm, the alerts that allowed airlines to reroute during the 2003 Halloween storms, and the forecasting that stopped a potential nuclear launch in 1967 are all products of the same infrastructure investment. Its continued funding is a public interest question.
Advocacy and community resilience guideSolar flare case study series
The Carrington Event 1859 covers the most powerful storm in recorded history. Quebec 1989 covers grid collapse in 92 seconds. Halloween 2003 covers the largest flare ever measured. May 2024 covers why the grid held through a G5 storm. Together, they document the full solar weather risk picture.
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