C H A P T E R
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Historical Space Weather Events
The October Storm (1989)
In 1989 – 130 years later after the Carrington Event – another extreme space weather event was about to hid Earth. This storm was one to be remembered as the largest magnetic storm of the 20’th century and has become the archetypal disturbance for examining geomagnetic hazards to power systems. This storm is known as the 1989 October Storm and lasted from March 10-13’th.
The lead-up to the October Storm started when a complex sunspot region (No. 5395) came into view on the eastern limb of the Sun’s disk. As the Sun rotated, this sunspot region produced multiple solar flares including 11 X-class solar flares (classified using the National Oceanic Atmospheric Administration (NOAA) Space Weather Scales and Benchmarks) throughout the 6-18th of March. The largest of these solar flares - classified as an X-class solar flare - occurred on the 6’th of March and was located near the Sun’s upper limb. If a Coronal Mass Ejection (CME) was to occur during this time, it would have missed Earth. However, as Region 5395 got closer to the center disk and, thus, began to face Earth, astronomers started to be concerned.
Image Credit: Ocean Navigator: Cartoon showing the Sun’s center disk and upper- and lower limb.
Image Credit: D.H. Boteler: Sunspot Region 5395, source of the March 1989 solar storm
On Friday March 10th 1989, astronomers witnessed a powerful explosion happening on the Sun. It was a CME classified by the NOAA Space Weather Scales and Benchmarks as an extreme event. The explosion was so intense that it could be compared to the energy level created from thousands of nuclear bombs exploding at the same time. On March 12 another CME had erupted but this time with Region 5395 closer to the center disk. Thus, it was now Earth-directed. Space weather forecast centers, therefore, started issuing warnings of a possible magnetic storm.
The CME traveled ~769 km/s and created an interplanetary shock front. It was composed of solar plasma (i.e., a gas of electrically charged particles) which interacted with Earth’s magnetic field, consequently causing an extreme geomagnetic storm.
Image Credit: Russ Nelson: Showing the solar flare, Coronal Mass Ejection and the location of its shock front.
Video Credit: NASA/Goddard Space Flight Center Conceptual Image Laboratory: Showing a Coronal Mass Ejection generating a reconnection between its own magnetic field and Earth’s magnetic field.
The storm started causing short-wave radio interference and jammed signals from Radio Free Europe into Russia. Shortly after, Aurora could be seen as far south as Florida and Cuba. As the October Storm occurred during the Cold War (1947-1991), some people worried that a nuclear first strike might have been in process. Others considered the intense Aurora to be associated with the Space Shuttle mission STS-29. Yet, the Space Shuttle was to be launched on March 13.
Furthermore, the intensity of the magnetic disturbance crated electrical currents in the ground beneath most of North America, leading to the charged particles interacting with the electrical power grid of Quebec, Canada. In less than a minute, Quebec lost half of its electrical power generators. Despite automatic load-reduction systems trying to restore a balance between the loads connected to the power grid and the massive loss of capacity, one by one, the load-reduction systems disconnected towns and regions. Domestic heating and lighting systems began to flicker and shut down. At 2:45:24 AM, a power swing was triggered in the utility lines belonging to the 2,200 megawatt Churchill Falls Generator Complex. 8 seconds later – at 2:45:32 AM - the entire Quebec power grid collapsed, leading millions of people without electrical power for 9-12 hours. The CME impact on the power grid system led to cascading events that took place so fast that operators could not react in time.
The temperatures in Toronto were ~-6.8 degrees Celsius at night and 1.6 degrees Celsius during daytime. This meant that the consequences of the power outage were felt very quickly by citizens, as homes were starting to get so cold that people woke up before their planned time, ate their cold breakfast in the dark, and left for work.
Montreal - a city in the province of Quebec - houses over 3 million people and is famous for its 30 km of long underground electrical-lit walkway system. The underground walkway links 60 buildings, universities, shops and businesses together. Over 500.000 people use this underground route each day to avoid the cold winter air. Yet, during the 1989 October Storm, people suddenly found themselves plunged into complete darkness with only the battery-powered safety lights to guide them through the tunnels.
Those who did not use the underground walkway system would soon find themselves stuck in traffic and trying to navigate through intersections without operating streetlights or traffic control systems. The power outage forced schools and businesses to close down and it kept the Montreal Metro shut down during the morning rush hours. Furthermore, the Dorval Airport got paralyzed and flights got delayed. No flight could land or takeoff until the power had been restored due to their dependency on the Global Navigation Satellite System (GNSS) and High Frequency (HF) Radio to establish contact with air traffic control (ATC) facilities.
The power outage in Quebec did, however, not only have consequences for Canada. Whilst Quebec slowly got their power restored by 10.00 AM, the power supplier - Hydro-Quebec – found themselves having issues with re-starting their power lines and transformers. From the moment the space weather event occurred and until Hydro-Quebec’s power was restored, the New York Power lost 150 megawatts and the New England Power Pool lost 1410 megawatts. Furthermore, 96 electrical utilities in New England experienced service interruptions. In the U.S. over 200 power grid problems occurred across its states within only minutes of the start of the geomagnetic storm. The electrical power pool serving the Northeast of America were very close to collapse as well.
Another power supplier at the time named Alleghney located in Pennsylvania lost 10 of its 24 Volt Ampere Reactive (VAR) capacitors as they were automatically taken off-line to avoid damage. Reactive power is the power released and stored by capacitors and inductors. It provides the function of regulating voltage levels in transmission lines, ensuring a smooth supply of real power. Furthermore, the Public Service Electric and Gas Company of New Jersey experienced overheating and permanent insulation damage. Whilst they had a backup transformer, it took them 6 months to install it. Meanwhile, a replacement of electricity was bought for ~400.000 USD from another power supplier in order to keep the residents of the East Coast from ending in a power outage.
In the space environment surrounding Earth, communication satellites had to be manually repointed from the ground as the local field polarity reversed their direction, nearly causing them to flip upside down. In the polar orbit, satellites tumbled out of control for several hours. The Geostationary Operational Environmental Satellite (GOES) was interrupted, consequently causing the loss of weather images. The Tracking and Data Relay Satellite System (TDRS-1) recorded over 250 anomalies caused by the increasement of particles interacting with its interior.
Image Credit: Unknown: Cartoon showing equatorial and polar orbit.
Issues were also detected onboard the Space Shuttle Discovery, where a sensor detected high pressure readings on one of the shuttles hydrogen fuel cells. Engineers tried to understand the data in order to advise whether to end the mission one day earlier than the expected day, yet without success. In addition, astronauts onboard the International Space Station (ISS) located ~400 km above sea level and protected by Earth’s magnetic field were warned about the event and advised to shelter themselves in the furthest interiors. However, despite this, astronauts still reported seeing flashes with their eyes closed.
The October Storm is now acknowledged as a legendary story among electrical engineers and space scientists. Additionally, it is a testament to that, in fact, space weather can affect space and terrestrial infrastructures. Solar storms like that of the October Storm are rare and although space weather forecast capabilities have gotten much better, it is still difficult to forecast these events.
We know that solar flares originate from sunspots and these have a cycle. Within a sunspot’s cycle it can produce ~1-3 large storms. It is, therefore, a matter of chance, whether a sunspot could cause an event powerful enough to trigger a Coronal Mass Ejection which furtherly could create a geomagnetic storm at the level created in 1989.
Today, it is not completely clear what a geomagnetic storm like that created during the October Storm could do to our current space and terrestrial infrastructures. Although, the space weather community has an idea. An event of the size of the October Storm is assumed to increase the risk of widespread voltage control problems and protective systems problems. It could cause power grid blackouts or a total power grid collapse. Furthermore, it could cause damage to transformers and currents in pipelines.
In space, it could increase the risk of extensive surface charging on spacecrafts and orientation problems and issues regarding tracking satellites. It could also cause issues in tracking debris and the performance of satellite maneuvers. Depending on where the International Space Station (ISS) is located on its orbital pathway around Earth, the exposure to space radiation and the impact would differ.
Sources
NASA (2009): https://gordonwatts.com/TheDayTheSunBroughtDarkness_NASA-viaWAYBACK-MACHINE.pdf
D.H. Boteler (2019): A 21st Century View of the March 1989 Magnetic Storm. AGU space Weather. Vol. 17, Issue 10. DOI: https://doi.org/10.1029/2019SW002278.
(1994): Global ionospheric effects of the October 1989 geomagnetic storm. Journal of Geophysical Research. Vol. 99, Issue A4. DOI: https://ui.adsabs.harvard.edu/link_gateway/1994JGR....99.6201Y/doi:10.1029/93JA02543.
