Around 10pm on September 4th, 2012, fifteen Outward Bound instructors rode crammed in a van driving down MN-11, which roughly follows the border between Minnesota and Ontario. After twelve hours of driving back from the Bloodvein River, we were still hours from home. We resigned to not making it home before our midnight driving curfew. The prairie-turned-farms stretched flatly away from both shoulders. A past-full moon hung golden above the horizon. Few lights besides the moon threatened the total darkness of rural northern Minnesota.

It started slowly. Folks on the driver’s side of the van noticed a shimmer along the northern horizon. Soft curtains of light appeared out of the dark backdrop. As we woke our sleeping fellow passengers, the light turned faintly green. I pressed my forehead against the window, transfixed by the undulating green movement wholly separate from the van’s progress down the highway. More of the fifteen awoke and stared at the incongruous light. As if by understood consent, the driver pulled over when she reached a safe spot. We piled out of the van. Hushed, we gazed northward. The movement in the sky was more vivid now that I was motionless. I stood awestruck.

That night in northern Minnesota was only my second experience seeing the aurora borealis, or northern lights. The first occurred earlier this summer, while I stood on the edge of the Kawishiwi River in late July. Before this summer, however, I’d been long skunked. My 2001 dogsledding and cross-country skiing course yielded a spectacular lunar halo, but no aurora. Subsequent trips to the Boundary Waters in fall and winter as an instructor proved to be similarly disappointing where the northern lights were concerned.

I have high hopes for the 2012-2013 winter season, however. Solar activity approaches an 11-year maximum, and solar maxima mean strong aurora events. The number and intensity of sunspots, solar flares, and coronal mass ejections (CMEs) wax and wane in 11-year cycles. Our current cycle, Solar Cycle 24, began on January 4, 2008. The maximum projected for fall 2013 looks weaker than other historical maxima, but could still trigger extreme space weather. When the sun is active, solar flares and CMEs send intense bursts of charged particles hurtling toward Earth’s magnetic sphere, the outer layer of the atmosphere. The sun’s electrons and protons follow the Earth’s magnetic field to the uppermost air particles, where the added energy excites the atmospheric atoms. To return to their normal energy levels, the atoms release energy in the form of light. Oxygen tends to emit yellow-greens and deep reds, while nitrogen creates violets and blues. The fluid path of the sun’s charged particles creates the mesmerizing shimmer.

While solar storms and their resulting northern lights occur at all times of year, winter provides optimum viewing opportunities. Long winter nights increase the time the sky acts as a canvas for the stunning light shows. Far removed from city lights, the Boundary Waters protects the aurora borealis from light pollution that would otherwise mask their appearance. Spectacular displays have already lit Minnesota’s skies in April, July, and September. I expect this winter will bring even more. Won’t you join us in finding out?

 

 

For aurora viewing resources, including forecasts, visit:

Aurora Forecast, University of Alaska – Fairbanks Geophysical Institute

Space Weather

Space Weather Now (NOAA)

Aurora How-To (Aurora Hunter)

 

For more technical information on the aurora borealis and solar cycles, visit:

Aurora Borealis, Encyclopedia of the Earth

NASA Solar Cycle Prediction

NOAA Arctic Theme Page

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