On March 22, the sun unleashed a powerful X-class solar flare that resulted in a coronal mass ejection (CME) reaching Earth on March 24. This event triggered a severe G4-class geomagnetic storm, the strongest seen since 2017.
Geomagnetic storms occur when disruptions in Earth’s magnetic field are caused by large releases of plasma and magnetic fields from the sun’s atmosphere. As a result of this recent storm, the National Oceanic and Atmospheric Administration (NOAA) issued an alert warning of potential auroras being visible as far south as Alabama to northern California.
However, despite the anticipation for spectacular northern lights displays, the aurora activity was limited due to a strong northward Bz shift. Bz refers to the orientation of the interplanetary magnetic field, with a southward Bz allowing for auroras to occur by connecting with Earth’s magnetosphere. In contrast, a northward Bz acts as a “closed door” preventing dramatic displays of auroras.
As a result of this shift in the Bz orientation, the potential for seeing the northern lights was diminished. While the geomagnetic storm was powerful, it did not result in the anticipated colorful light displays in the sky. Nonetheless, the event serves as a reminder of the sun’s power and its ability to impact Earth’s magnetic field.
