M8.2 solar flare, Strong G4 geomagnetic storm watch

    Msg ID:     104606
    Message Type:  Geomagnetic Disturbance Action 
    Priority:     Action
    Effective Start Time:  06.01.2025 09:31
    Effective End Time:  06.01.2025 12:25
    Regions  COMED

    A Geomagnetic Disturbance Action has been issued as of 09:31 on 06.01.2025 to protect
    the power system from damage or disruptions due to increased geomagnetic activity.

Background:

These messages are from the US east coast power grid control room in Valley Forge, PA sending to people at generating stations and other key control centers. This is a slow-moving event. If the grid was stressed, there would be "Pre-Emergency Load Reduction" and "Conservative Operation" actions ordered. If there was real trouble, there would be many more actions. But things never got beyond preparing for trouble.

A geomagnetic disturbance event in 1989 caused transformer damage leading to outages. The solar flux going between power lines and conductive ground induces DC currents into the ground and lines, so that ground potential is different at different points. This causes partial saturation of transformers, and heating. That wasn't noticed until it was too late. So now, DC current in some key AC lines is monitored continuously, so power levels can be reduced if necessary.

Training materials for understanding this:[1] Start at slide 21.

Background info on how a power grid works.[2] Start with "PJM 101"

[1] https://pjm.adobeconnect.com/p63ultsdb2v/

[2] https://www.pjm.com/training/training-resources

We might see several of these per year during a solar maximum. So maybe we get some nice auroras.

Edit, TIL: Though the G4 is a different issue, which classifies the impact of a solar flare on our earth. These range from G1 (minor) to G5 (extreme). This means that it can disrupt radio communications and GPS, put stress on power grids and, interestingly, increase satellite drag. G4 storms are rare events and occur only a few times per 11-year solar cycle.

https://community.spaceweatherlive.com/topic/3947-ar14100-m8...

Although it often sounds like people throwing fancy words around just to sound smart. And their predictions mostly dont work out

What could I subscribe to so as to be notified when such events happen?

https://www.swpc.noaa.gov/news/cme-passage-continues-g3-g4-s...

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NOAA map (https://www.swpc.noaa.gov/products/aurora-30-minute-forecast) shows huge auroras were at ~7-9 UTC and now are gone

https://solarham.com/ says "arrived faster than expected" and "threshold was reached at 08:00 UTC"

and the website linked, the https://www.spaceweatherlive.com/en/.html says "14:00 UTC - Geomagnetic activity Severe G4 geomagnetic storm (Kp8)" followed by "17:30 UTC - Geomagnetic activity Minor G1 geomagnetic storm"