If you missed the incredibly colorful sunset last night check out the photos below. What we witnessed is rare mammatus clouds (sagging pouch-like structures, an indication that a severe thunderstorm has passed) lit up by the Northern Lights (Aurora borealis). The color of the sky changed from yellow to orange to red to purple within minutes.

“People throughout the city stopped to witness the incredible sunset post storm. Cars were pulled over. Photographers were lined up the Walnut Street Bridge. Pedestrians on camera phones were snapping the incredible evening hues. The best way to describe the sunset? Mystical.” – Photo and quote by reader Veronica Alvarez

By the way, there will be another chance to see the Northern Lights tonight. Here‘s some more information.