Continued G4 (Severe) Geomagnetic Storming Observed
Meaning of G4: http://www.swpc.noaa.gov/noaa-scales-explanation"Power systems: Possible widespread voltage control problems and some protective systems will mistakenly trip out key assets from the grid.Spacecraft operations: May experience surface charging and tracking problems, corrections may be needed for orientation problems.Other systems: Induced pipeline currents affect preventive measures, HF radio propagation sporadic, satellite navigation degraded for hours, low-frequency radio navigation disrupted, and aurora has been seen as low as Alabama and northern California (typically 45° geomagnetic lat.)."Apparently there are 100 of these per 11-year solar cycle.