Part of the scale is based on a ‘K’ index, sometimes called a ‘Planetary-K’ index, stylized as “Kp.” This reading quantifies the horizontal movement in the earth’s magnetic field over three-hour intervals, with 0 being totally calm (marked by green), and five or more indicating a geomagnetic storm is occurring (marked by red). The top of the scale is 9, reflecting an extreme storm.

The colors, intensity, shape, and coverage of an aurora borealis event correlate to the Kp index as such: Kp0 means we might see faint green, from Kp3 we might see some yellows, Kp4 brings pink, Kp5 brings blue and purple, and at Kp8 red becomes part of the mix. Thus, greens are common with lower Kp values, but the blues, purples, and red become visible in only more intense Geomagnetic storms.

0 being totally calm (marked by green), and five or more indicating a geomagnetic storm is occurring (marked by red). The top of the scale is 9, reflecting an extreme storm.

The colors, intensity, shape, and coverage of an aurora borealis event correlate to the Kp index as such: Kp0 means we might see faint green, from Kp3 we might see some yellows, Kp4 brings pink, Kp5 brings blue and pur

0 being totally calm (marked by green), and five or more indicating a geomagnetic storm is occurring (marked by red). The top of the scale is 9, reflecting an extreme storm.

The colors, intensity, shape, and coverage of an aurora borealis event correlate to the Kp index as such: Kp0 means we might see faint green, from Kp3 we might see some yellows, Kp4 brings pink, Kp5 brings blue and pur

0 being totally calm (marked by green), and five or more indicating a geomagnetic storm is occurring (marked by red). The top of the scale is 9, reflecting an extreme storm.

The colors, intensity, shape, and coverage of an aurora borealis event correlate to the Kp index as such: Kp0 means we might see faint green, from Kp3 we might see some yellows, Kp4 brings pink, Kp5 brings blue and pur

0 being totally calm (marked by green), and five or more indicating a geomagnetic storm is occurring (marked by red). The top of the scale is 9, reflecting an extreme storm.

The colors, intensity, shape, and coverage of an aurora borealis event correlate to the Kp index as such: Kp0 means we might see faint green, from Kp3 we might see some yellows, Kp4 brings pink, Kp5 brings blue and pur