GADS: GMD Event Reporting Reminder

May 10 May 12, 2024


Following the recent geomagnetic storm on May 10 May 12, 2024, NERC is asking that all entities carefully review outages during this time period and consider whether GMD may be a primary, secondary or contributing cause of the event. Some ways that generator performance can be affected during a GMD event include increased heating in generator rotors, vibration and torsional stress, and relay alarming, operation, or erratic behavior. Generator step-up transformers can also be susceptible to abnormal heating, increased reactive power consumption, and vibration during GMD events. Additional information can be found in the applicable GADS Data Reporting Instruction (DRI) and NERC Special Reliability Assessment: Effects of Geomagnetic Disturbances on the Bulk Power System (February, 2012).


When reporting in the Generating Availability Data System, we ask that you report any such GMD-related events by designating the primary or additional cause codes using one of the following:


              Conventional 9025 (Applicable Appendix of GADS DRI)

              Wind 19025 (Appendix J of Wind DRI)

              Solar 29025 (Appendix K of Solar DRI)


For the Contributing Operating Condition, we ask that you use Code 5, Geomagnetic Disturbance (this includes pre-emptive actions as well). Accurate reporting for this event is crucial to assess the impact of this major GMD event.


The Q2 reporting deadline is November 15, 2024. However, given the significance of this event, early reporting is strongly encouraged to support analysis efforts. Please direct any reporting questions to or


For more information or assistance, please contact or

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