response readiness for solar storms
We’ve had a handful of headlines in the past few years that sound like the opening of a sci-fi story. There was one on Wednesday, “Huge Sunspot Pointed Directly at Earth…”.
Sunspot AR13089 is in the news because it is capable of producing X-class solar flares. X-class is the highest level. Levels above X are numbered. An X10 flare is 10 times more powerful than X1, and X20 is 2 times more powerful than X10. An X1 flare hitting Earth is a minor, localized disruption. X20 could be a serious problem: a complete radio blackout on the sunlight side of Earth, satellite disruptions for many hours, and navigation system outages possibly for days. A Coronal Mass Ejection (CME) from an X20 flare could be a disaster. Flares don’t always have CMEs. A large and fast CME hitting Earth would trigger geomagnetic storms which could cause irreparable damage to satellites and the grid.
The National Oceanic and Atmospheric Administration (NOAA) put a 10% probability of an X-class flare hitting Earth in the next 2 days. I spoke with Bill Murtagh who works for the NOAA out of the Space Weather Prediction Center (SWPC) in Boulder, CO. The NOAA is responsible for monitoring and predicting space weather. Bill said, based on recent activity, he would be surprised if this sunspot produced an X-class flare. Since Wednesday the spot has rotated to the right on the visible face of the sun, meaning if a flare was to occur the associated CME would have minimal effects on Earth.
Bill was on-duty for two historic flares: March 1989when he was at the Palehua Solar Observatory in Hawaii and October 2003 when he was at the SWPC. They both produced CMEs that hit Earth and caused serious problems but they weren’t catastrophic. Bill had this to say about CME prediction modeling:
Larger flares are more likely to produce CMEs. A fast CME would hit us in about 15 hours. A slow one would take 90 hours. A flare interferes with signals, but a CME and the resulting geomagnetic storms actually can damage and degrade satellite and power grid hardware.
A holy grail [in space weather prediction modeling] is the orientation of the magnetic field of a CME. A CME is a large magnet. Modeling how it will propagate from the sun and how it will couple with Earth’s magnetic field is very tricky. There are many gaps in the science and a lot of work is underway in the research community to help fill in those gaps.
No article about solar flares would be complete without mentioning the Carrington Event. The largest solar flare ever observed happened on September 1, 1859 (163 years and 2 days ago). It led to radio blackouts, fires in telegraph stations, and auroras visible as far south as the Caribbean. Scientists have repeatedly warned that this will happen again eventually.
In the event of a major solar storm the NOAA would place “hotline calls to power grid operators in the U.S. and Canada”, who would phone-tree to sound the alarm. Grid operators would put individualized plans into action based on their vulnerability which is typically dependent on “latitude, proximity to the ocean, and geology”; all variables that effect how geomagnetically induced currents propagate through the Earth and specific infrastructure.
This is a busy weekend for the NOAA as they are coordinating with NASA on the Artemis I launch: part of a mission to establish a sustainable presence on the Moon to prepare for missions to Mars. Special thanks to Bill Murtagh for his contribution.