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Commercial Property

Space Weather and Commercial Property Insurance

Catherine L Trischan | April 24, 2026

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oversized sun with solar flares extremely close to Earth

It is late summer 1859, and you are working as a telegraph operator in Pittsburgh. Suddenly, sparks are coming from your telegraph machine, igniting the recording tape and shocking you. Around the same time, auroras, normally visible only in high latitudes, are seen in the tropics, and magnetic disturbances cause unusual activity in the instruments that measure Earth's magnetism. What is happening?

The space weather event that occurred in 1859 is known as the Carrington Event, and it was watched by astronomers around the world who first saw a solar flare, the flash that often precedes a coronal mass ejection (CME), a burst of magnetized plasma from the sun. This solar storm traveled over 90 million miles in 17.6 hours before reaching Earth's magnetosphere, the region of space surrounding Earth where Earth's magnetic field is most intense. Energy was transferred from the CME to the magnetosphere, which resulted in a geomagnetic storm that disrupted technology on Earth.

Consider now the use of technology in 1859 as compared to 2026. A 2013 report by Lloyd's in conjunction with Atmospheric and Environmental Research Inc., Solar Storm Risk to the North American Electric Grid, estimates that, if the Carrington Event happened today, certain parts of the US could be without power for between 16 days and 2 years with a total event cost of up to $2.6 trillion in the US alone.

The Carrington Event happened over 166 years ago, and although it was the most significant solar storm to affect Earth, it is not the only one.

  • In May 1921, a solar storm resulted in the shutdown of the signal and switching system of the New York Central Railroad and the loss of a railroad station building due to fire that spread from a telegraph system.
  • In March 1989, a CME reached Earth's magnetic field and caused the Hydro-Quebec power grid to fail; a 9-hour blackout in Quebec affected 6 million people. That storm also caused irreparable damage to a transformer at a nuclear station in New Jersey.
  • In July 2012, there was a solar storm as powerful as that in the Carrington Event, which, fortunately, missed Earth.

Smaller storms, about half as intense as the Carrington Event, happen about every 50 years. The solar maximum, which occurs every 11 years, is a period of peak solar activity where the sun's magnetic poles flip, and the solar maximum is characterized by an increase in the number of solar flares and CMEs. This type of space weather impacts satellites, aircraft, communication networks, GPS systems, pipelines, and power grids. Extra high voltage transformers are particularly vulnerable to damage by geomagnetically induced currents in the ground that result from these storms.

Damage to property results, as does the loss of income due to lack of power, disruption of transportation and communication systems, and supply chain bottlenecks. The effect that solar flares, CMEs, geomagnetic storms, and other space weather can have on commercial insureds has been known for some time. It is only now, though, that the exposure is being addressed in the most commonly used commercial property forms.

Space Weather Exclusion

Insurance Services Office, Inc. (ISO), has recently introduced an endorsement, Space Weather Exclusion (CP 10 79 06 26). The endorsement is effective beginning in June 2026 and is considered mandatory according to ISO rules. The endorsement adds the following exclusion, prefaced with anticoncurrent causation language, to commercial property policies.

The following exclusion is added:

  • We will not pay for loss or damage caused directly or indirectly by the following. Such loss or damage is excluded regardless of any other cause or event that contributes concurrently or in any sequence to the loss.

  • Space Weather

    Space weather, meaning any condition or event originating beyond the Earth's upper atmosphere that interacts with Earth's magnetosphere, ionosphere, thermosphere or upper atmosphere, that disrupts or otherwise interferes with property that is space-borne, atmospheric or ground-based. Such condition or event includes, but is not limited to, solar wind, space particles, space electromagnetic radiation, solar energetic proton events, high-speed solar wind streams, coronal mass ejections, solar flares or geomagnetic storms.

It is interesting to note that, unlike some other exclusions that follow anticoncurrent causation language, there is no exception for damage by fire that may result from the excluded peril. Because, in some jurisdictions, coverage for loss by ensuing fire must be preserved, ISO has introduced a second endorsement, Space Weather Exclusion with Ensuing Cause of Loss Exception (CP 10 80 06 26), which adds the following language to the exclusion.

B. Exception Covering Certain Fire Losses

If a space weather condition or event results in fire, we will pay for the loss or damage caused by that fire. Such coverage for fire applies only to direct loss or damage by fire to Covered Property. Therefore, for example, the coverage does not apply to insurance provided under Business Income and/or Extra Expense coverage forms or endorsements which apply to those forms, or to the Legal Liability Coverage Form or the Leasehold Interest Coverage Form.

Note that this exception applies only to direct damage by fire, not to any time element loss, such as business income or extra expense. For many commercial insureds, these indirect losses are likely to cause more financial harm than that caused by fire damage resulting from space weather.

Special Form Causes of Loss Exclusions

There are two exclusions in the Causes of Loss—Special Form (CP 10 30 09 17) that already remove coverage for much of the direct and indirect loss caused by space weather: nuclear hazard and utility services.

Nuclear Hazard

One of the concerns with space weather is the effect that radioactive material may have on satellite operations as well as communication and navigation systems. The National Oceanic and Atmospheric Administration (NOAA) has created Space Weather Scales to describe the effect of current and future space weather conditions on people and systems. 1

Solar radiation storms are rated on a scale of S1 to S5, with S1 having only a minor impact on high-frequency radio in the polar regions. S5 results in satellites that are rendered useless and a complete blackout of high-frequency communications through the polar regions, along with position errors that make navigation operations extremely difficult.

Even without the Space Weather Exclusion, the ISO special form's nuclear hazard exclusion applies to losses involving nuclear reaction or radiation; the exclusion is prefaced with anticoncurrent causation language.

B. Exclusions

1. We will not pay for loss or damage caused directly or indirectly by any of the following. Such loss or damage is excluded regardless of any other cause or event that contributes concurrently or in any sequence to the loss.

  • d. Nuclear Hazard

  • Nuclear reaction or radiation, or radioactive contamination, however caused.

  • But if nuclear reaction or radiation, or radioactive contamination, results in fire, we will pay for the loss or damage caused by that fire.

One important difference between the nuclear hazard exclusion and Space Weather Exclusion (CP 10 79 06 26) is that the nuclear hazard exclusion has an exception for damage by ensuing fire, while the Space Weather Exclusion does not.

Utility Services

One of the biggest exposures to commercial insureds after a space weather event is the loss of power. Even without the Space Weather Exclusion, the ISO special form excludes power failure with the utility services exclusion, an exclusion prefaced with anticoncurrent causation language.

B. Exclusions

1. We will not pay for loss or damage caused directly or indirectly by any of the following. Such loss or damage is excluded regardless of any other cause or event that contributes concurrently or in any sequence to the loss.

  • e. Utility Services

    The failure of power, communication, water or other utility service supplied to the described premises, however caused, if the failure:

    (1) Originates away from the described premises; or

    (2) Originates at the described premises, but only if such failure involves equipment used to supply the utility service to the described premises from a source away from the described premises.

    Failure of any utility service includes lack of sufficient capacity and reduction in supply.

    Loss or damage caused by a surge of power is also excluded, if the surge would not have occurred but for an event causing a failure of power.

    But if the failure or surge of power, or the failure of communication, water or other utility service, results in a Covered Cause of Loss, we will pay for the loss or damage caused by that Covered Cause of Loss.

    Communication services include but are not limited to service relating to Internet access or access to any electronic, cellular or satellite network.

As was seen with the nuclear hazard exclusion, the utility services exclusion has an exception for damage by ensuing fire, while the Space Weather Exclusion (CP 10 79 06 26) does not.

It is common for commercial property policies to add back some coverage for utility services interruption through endorsements such as Utility Services—Direct Damage (CP 04 17 10 12) and Utility Services—Time Element (CP 15 45 09 17). With the Space Weather Exclusion, loss of power due to space weather is not a covered cause of loss, so the endorsements will not provide coverage.

Conclusion

Concerns over space weather and its effect on commercial insureds are not new. Based on the exclusions already in ISO forms, it is unlikely that coverage would apply to many losses involving space weather. However, ISO's new endorsement makes it clear that the property policies commonly written do not intend to respond to any direct or indirect losses involving space weather.


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Footnotes

1 "NOAA Space Weather Scales," NOAA and National Weather Service Space Weather Prediction Center, accessed on April 11, 2026.