February 18, 2017 Auroras
Spider Lake, Chippewa National Forest
A high speed stream of solar wind and a somewhat southward Bz (-5 nT) brought auroras to northern Minnesota. It had been a exceptionally warm day with highs near 60 degrees, but a "cold" front had come through, and temperatures were dropping into the 40s. The sky was clear, so the 40-degree temperatures did not melt the snow any further. Solar wind conditions looked good, so I headed out. The moon would rise just after midnight, so I probably would not be out too late, as the bright moon on snow tends to make auroras less visible, and I wasn't expecting a huge show, anyway.
I got out to the lake and saw a pretty nice auroral oval, which was a few degrees above the northern horizon. It was getting brighter, so I concluded an auroral substorm would occur soon, but that never happened. Also, a group of snowmobilers came out onto the lake, so I wanted to make myself less visible or at least not stand in the middle of the lake where they might be surprised to see me. By the time the snowmobilers had exited, the auroras were starting to dim. I was done shooting around 10:15 PM.
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| This is what the auroral oval looked like when I walked out onto Spider Lake. |
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| View from the island in the previous photo. |
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| A double-banded structure starts to appear. Could a substorm be near? |
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| There was no substorm. The auroras faded. |
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