Dazzling purples, yellows and a hint of green danced across the sky in central Minnesota early Sunday.
The northern lights are normally only visible at very high latitudes – like in Alaska and Canada, but on extremely active days the auroral oval expands to more southern latitudes, like Minnesota, according to the University of Minnesota.
That's what happened over the weekend. StormChasingVideo posted on its website saying, "A powerful G2 Class Geomagnetic Storm impacted the earth overnight and created a vivid display of the Aurora Borealis or northern lights over central Minnesota."
The Aurora Borealis is caused by gas particles colliding in the Earth's atmosphere with charged particles released from the sun's atmosphere, according to the New York Daily News. More disturbances on the sun mean a better chance to see the northern lights.
The color of the northern lights depends on the type of gas particles that are colliding, the Northern Lights Centre says. The most common colors are a pale yellowish-green, which is produced by oxygen molecules about 60 miles above the earth. All red northern lights are rare and produced by high-altitude oxygen at heights of up to 200 miles.
Nitrogen produces blue or purplish-red northern lights, the Northern Lights Centre notes.
Researches have found that the northern lights occur in a cycle – peaking roughly every 11 years. The Earth is just past the peak of a sunspot cycle, which makes 2014 a good year for viewing the northern lights, the St. Cloud Times reported in an article explaining more about celestial light shows in Minnesota.
The northern lights are visible year-round, but are generally the most vivid around the spring and fall equinoxes, Yahoo News reports. For more information on the best time and place to see the northern lights, check out the Geophysical Institute's detailed long-term and short-term forecast.
The Geophysical Institute notes that the northern lights should be visible to observers in Canada and the northern United States if the auroral index is four or more. Check the auroral index here.
SpaceWeather.com also has a northern lights forecast.