The geomagnetic storm I witnessed in Iceland on Oct 10 led to perhaps one of the brightest auroral events I had ever witnessed. Even with my eyes blinded by the headlights while driving, I could still see the reds and the pinks in the sky. The splash of color in the sky danced and morphed continuously, highlighting an intensity of storm that was off the charts. A few moments later, when I stopped to take a look, the bulk of the auroral activity was occurring in the southern half of the skies.
I had never seen such bright band of red span across the entire sky from east to west. These colors show up rarely and only during intense storms where the charged solar particles react with Oxygen above 200mi (320km). The typical aurora with green hues occurs from this same reaction occurring at much lower altitudes (60-190mi or 100-300km). This is also why you see the greens band below the reds.
This storm continued for the entire night, though it ebbed and flowed throughout. I was glad I had an opportunity to witness this.
Fjallsárlón
Iceland