Extreme Space Weather: Forewarned is Forearmed
Carrington Event
Just before noon on September 1st, 1859, a coronal mass ejection (CME) launched towards Earth from the Sun, crossing the immense distance of interplanetary space in just 17.6 hours. When it impacted the Earth’s magnetosphere, the resulting auroras illuminated the night sky brightly enough to read a newspaper by; they were visible at latitudes as low as Hawaii, Cuba, Mexico, and northern Australia. The geomagnetically induced currents (GIC) caused by the CME’s magnetic field coupling with the Earth’s set telegraph stations on fire, destroying documents, instrumentation, and causing disruptions in communications. The CME’s immense velocity of roughly 2300 km/s and estimated magnetic field of -81nT [1] were the primary factors of these dramatic effects. Disaster mitigation experts estimate the cost of such an event today to be anywhere between $0.6–2.6 trillion dollars[2]. This event became known as the Carrington Event, and has served as the benchmark for extreme solar events since.
March 1989 Geomagnetic Storm
On 10 March 1989, an X4.5 flare released a CME traveling at 760km/s through interplanetary space. As it crossed the interplanetary medium, on 12 March, an X7.3 flare released a CME traveling at a much faster 1320km/s. The resultant converging CME shocks impacted the Earth at 01:27UT and 07:23UT respectively, resulting in the most severe geomagnetic storm in the 20th century on record. The estimated southward magnetic field peaked at 60nT, with a proton flux of 3,500pfu, and the staggered arrival cleared the way for a Dst of -589 nT — the most severe on record since recordkeeping began. [3]
Visually, the impact was striking, with auroras stretching into the Caribbean and lasting for nearly two days. On a societal and economic level, the impact was more dire:
“the March 13 blackout was caused by the strongest magnetic storm ever recorded since the 735-kV power system was commissioned. At 2:45 a.m., the storm… tripped five lines from James Bay and caused a generation loss of 9,450 MW. With a load of some 21,350 MW at that moment, the system was unable to withstand this sudden loss and collapsed within seconds, thereby causing further loss of generation from Churchill Falls and Mania-Outardes.” [4]
The Hydro-Quebec power generating complex completely failed in 90 seconds due to cascading failures brought about by GICs, which went along the north-south lines of the region, stretching as far south as New Jersey, overwhelming transformers and their associated compensation mechanisms. Several polar orbit satellites lost control for several hours, with several satellites experiencing equipment malfunction/destruction and one high-latitude satellite experiencing episodic “tumbling” for days around the storm[5]. 6–9 million Canadians were without power for 9–12 hours. Estimated losses due to the blackout totaled $13.2 million CDN [6], though losses to second and third-order effects were not formally compiled into a report.
Halloween Event
Starting from 19 October and finally ending 5 November, 2003, the Sun launched 17 separate M5.0 to X 17.5–28 class flares, an unprecedented level of extreme activity that peaked with flares launched on the 28th, 29th of October and the 4th of November.
The 28 Oct CME launched towards the Earth at a speed exceeding 2125 km/s, followed by a CME on the 29th at an estimated 1948 km/s[18]. The maximum recorded proton flux over the active period was 29,500 pfu.
The resulting aurora, while fabulous, also heralded the dangers of this series of storms. Goddard’s Space Science Mission Operations Team estimated that 59% of NASA’s Earth and space science satellites were affected in one way or another, and teams of specialists spent days working around the clock to reestablish the locations of orbiting satellites [8]; Earth’s upper atmosphere absorbed approximately 3 terawatts of power, resulting in a sharp expansion, and increasing drag on over 2,000 satellites. The incredible quantities of charged particles rendered many satellites inoperable for the duration of the event, and is even suspected to have caused the loss of the $640 million ADEOS-2 spacecraft. [7]
Northern Europe experienced localized transformer failures and even system failures leading to full blackouts. Polar flights rerouted to avoid irradiating passengers, costing airlines anywhere from $10,000-$100,000 per flight rerouted. Astronauts aboard the ISS received a directive to shelter in a hardened section of the space station to protect themselves from the radiation. The resulting NOAA impact analyses created documents foundational to space weather policy regarding satellite and transformer hardening, and flight protocols.
Remarkably, these effects were not caused by the strongest flare, which was on November 4th. Despite being on the western limb of the solar disk, The GOES XRS instrument became saturated at the X17.5 level for 12 minutes during this flare, leading to a later re-assessment of an X28 level.
Gannon Event
On May 8th, 2024, 22:04–22:30 UTC, sunspot region AR3664, 15 times the diameter of Earth and rivaling the size of the sunspots observed before the Carrington Event, rotated to face the earth and fired off eight X-class flares and seven Earth-bound CMEs; the rapid-fire of CMEs with speeds ranging from 700–1500 km/s resulted in a merged complex structure that arrived simultaneously by 10 May 2024. Its recorded magnetic field of -50nT oriented southward allowed for particularly efficient coupling, leading to the a G5 (Severe) geomagnetic storm and incredible auroral display visible at extremely low latitudes, with documented sightings throughout all 50 states and as far south as the Florida Keys and Mexico. The sustained strength of the merged CME compressed the earth’s magnetosphere to never-before-recorded levels, and resulted in the temporary creation of a whole new radiation belt between the permanent Van Allen radiation belts. The heating of the ionosphere was severe enough to cause the loss/reentry of 12 Starlink (each roughly $1–2 million to build and launch) satellites [10], with most other satellites needing to perform correctional maneuvers to stay in their positions. Many had temporarily disabled instruments [9]. The most severe and documented effect, however, was in the agricultural sector, with GPS-dependent agricultural equipment affected by positional errors as large as 230 feet. Agricultural impact analyses estimate the losses to be in the $500–565 million range due to disruptions in the middle of peak planting season [11]; this is with appropriate mitigation and hardening measures.
18 Jan 2026
On January 18th 2026, at 17:27 UTC, an X1.9 class solar flare in active region 4341 was detected by satellites observing the Sun, triggering an R3 radio blackout over the Americas[12][13]. The flare peaked in strength at 18:09 UTC, and at 18:30 UTC, a full-halo coronal mass ejection (CME) was detected by GOES-19/CCOR-1, NOAA’s first operational geostationary coronagraph.
The flare itself released a massive proton flux, with SIDC getting readings of 1,990 proton flux units (pfu)[14], NOAA getting readings exceeding 10,000 pfu [12], and the Lebedev Physical Institute of the Russian Academy of Sciences getting values as high as 37,000pfu [16]. As the CME propagated through interplanetary space and reached L1, proton density increased from ~3 protons per cubic centimeter (p/cc) to ~29 p/cc, and the temperature increased from a mild ~65,000 Kelvin (K) to a balmy ~900,000 K [17]. Solar wind speed reached 1,000 km/s, and the baseline total magnetic field strength (Bt, measured in nanotesla (nT)) increased from ~6 nT to ~91 nT –over 15 times more intense.[15]
When the CME finally came into contact with the Earth’s magnetosphere, its speed, magnetic field intensity, initial southward orientation, and size were all favorable conditions for an extraordinary electromagnetically disruptive event. However, as the intensity of the geomagnetic storm reached G4, the magnetic orientation of the CME flipped northward, a significantly less efficient configuration for magnetic coupling that softened the overall impact on Earth, leading only to some communication disruptions in the polar regions and an auroral display in regions much closer to the equator than normal, with aurora borealis observed as far south as Alabama, USA.
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However, when looking at the characteristics of this CME and comparing them to significant space weather events of the past, it becomes clear that should the magnetic orientation of the CME have remained in a southward configuration, the effects on the surface of the Earth would have been significantly more drastic. Of all the events listed above, it is worth noting that only the January 18–19 event was caused by a single ultra-fast CME, with no enhancing or helping factors, much like the Carrington Event. A large, lone, high speed CME with a strong magnetic field oriented southward is all it would take to substantially negatively impact infrastructure, supply lines, and daily life.
What can we do?
Our greatest vulnerability is our lack of ability to reliably predict when CMEs will happen, followed by our lack of ability to comprehensively model them in transit to Earth; of the two, the latter is one we can address with our current knowledge and technology. Currently, we have angles of observation of the Sun constrained by satellites orbiting it in the same plane, which results in a periodic reduction of vantage points when they align on the Sun-Earth line. A third observational satellite, ideally in a polar or high-latitude orbit around the sun, or at the L5 Lagrange point, would present us with enough consistently different observation points off the Sun-Earth line to more accurately model the structure, velocity, and direction of a CME long before impact. We have been quite lucky with the impacts of these extreme events, but as history has demonstrated, our increasing dependence on satellites, telecommunications, and delicate electronics has and will continue to correspondingly increase our vulnerability to these extreme space weather events.
Citations:
[1]: Gopalswamy, N. (2021), Effects of extreme space weather on society, presentation at the International Space Weather Initiative Online Workshop 2021, United Nations Office for Outer Space Affairs (UNOOSA), Vienna, Austria, 26 pp., https://www.unoosa.org/documents/pdf/psa/activities/2021/iswi2021/ISWI_2021_01.pdf (Accessed March 2, 2026).
[2]Lloyd’s of London (2013), Solar storm risk to the North American electric grid, Lloyd’s, London, U.K., 21 pp., https://assets.lloyds.com/assets/pdf-solar-storm-risk-to-the-north-american-electric-grid/1/pdf-Solar-Storm-Risk-to-the-North-American-Electric-Grid.pdf (Accessed March 2, 2026)
[3] Boteler, D. H. (2019). A 21st century view of the March 1989 magnetic storm. https://doi.org/10.1029/2019SW002278
[4] Australian Space Weather Forecasting Centre (ASWFC) (2025), Power Failure in Canada During 1989 , Bureau of Meteorology, Australia, https://www.sws.bom.gov.au/Educational/1/3/12 (Accessed March 2, 2026).
sws.bom
[5] Bolduc, L. (2002), GIC observations and studies in the Hydro‑Québec power system, Journal of Atmospheric and Solar‑Terrestrial Physics, https://doi.org/10.1016/S1364‑6826(02)00128‑1
[6] Allen, J. H. (1989), Solar and geomagnetic activity during March 1989 and later months and their consequences at Earth and in near‑Earth space, pp. 24–27, https://www.spis.org/archives/projects/spine/home/tools/sctc/Vnd/78b71406c0a80014001fb2a4bc508949/5th_Solar_and_Geomagnetic_Activity_during_March_1989_a_5.pdf (Accessed March 5, 2026).
[7] National Weather Service (2004), Intense space weather storms: October 19–November 7, 2003, Service Assessment, U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Weather Service, Silver Spring, Md., 67 pp., https://www.weather.gov/media/publications/assessments/SWstorms_assessment.pdf (Accessed March 10, 2026).
[8] Berger, T. E., Holzinger, M. J., Sutton, E. K., & Thayer, J. P. (2020). Flying through uncertainty. Space Weather, 18, e2019SW002373. https://doi.org/10.1029/2019SW002373
[9] NASA (2025), What NASA is learning from the biggest geomagnetic storm in 20 years, NASA Science — Heliophysics, National Aeronautics and Space Administration, Washington, D.C., https://science.nasa.gov/science-research/heliophysics/what-nasa-is-learning-from-the-biggest-geomagnetic-storm-in-20-years/ (Accessed April 28, 2026).
[10] Ashruf, A., P. Bhaskar, and S. C. Chapman (2024), Loss of 12 Starlink satellites due to pre‑conditioning of intense space weather activity surrounding the extreme geomagnetic storm of May 2024, arXiv preprint, arXiv:2410.16254, https://arxiv.org/abs/2410.16254
[11] Griffin, T., D. Knipp, C. Shank, C. Skov, and R. Leamon (2025), Impact of the Gannon Storm on corn production across the Midwestern USA, Working paper, Kansas State University, Manhattan, Kan., https://doi.org/10.5281/zenodo.14976490.
[12]NOAA Space Weather Prediction Center (SWPC) (2026), S4 (Severe) solar radiation storm in progress, January 19th, 2026, NOAA Space Weather Prediction Center, Boulder, Colo., http://www.swpc.noaa.gov/news/s4-severe-solar-radiation-storm-progress-january-19th-2026 (Accessed March 2, 2026).
[13]NOAA Space Weather Prediction Center (SWPC) (2026a), X‑class flare activity observed — 18 January 2026, NOAA SWPC, Boulder, Colo., http://www.swpc.noaa.gov/news/x-class-flare-activity-observed-18-january-2026 (Accessed March 2, 2026)
[14]Solar Influences Data Analysis Center (SIDC) (2026), X1.9 flare, Royal Observatory of Belgium, Brussels, Belgium, https://www.sidc.be/article/x19-flare (Accessed March 20, 2026).
[15]Solar Influences Data Analysis Center (SIDC), Extreme solar wind conditions, Royal Observatory of Belgium, Brussels, Belgium, https://www.sidc.be/article/extreme-solar-wind-conditions (Accessed March 20, 2026).
[16] Laboratory of X‑Ray Astronomy of the Sun (XRAS) (2026), project diary: Solar activity updates, Lebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia, https://xras.ru/en/project_diary.html?post_id=3232 (Accessed March 20, 2026)
[17] NASA Community Coordinated Modeling Center (CCMC) (2026), CME Scoreboard prediction detail for the 18 January 2026 CME (event ID 5196), NASA Goddard Space Flight Center, Greenbelt, Md., https://kauai.ccmc.gsfc.nasa.gov/CMEscoreboard/prediction/detail/5196 (Accessed March 2, 2026).
[18] Gopalswamy, N., S. Yashiro, and S. Akiyama (2006), Highlights of the October — November 2003 Extreme Events, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA, https://cdaw.gsfc.nasa.gov/publications/gopal/gopal2006SEE_20.pdf (Accessed April 3, 2026)
