Big Auroras Light Up Memorial Day Weekend

The aurora started at dusk yesterday and raged all night. Soft-edged patches pulsed toward the zenith around midnight (CDT). Credit: Bob King

Wow! What a night. I didn’t get to bed until 1:30 this morning. No regrets though. The display of oozing, expanding, pulsing and darting northern lights was second to none. What made this round of aurora so interesting for me was the nearly complete absence of sharp edges. Everything I saw — even the occasional little rays — appeared soft and ghost-like. Imagine Casper the Friendly Ghost swooshing about and you can kind of picture it. That is, if you didn’t witness the show yourself, which I hope you did.

How about an aurora from California? Dan McBride of Sacramento drove for 1 ½ hours to a helipad at Big Hill Lookout. “I could barely see it, but after my first test shot I knew I had just caught purple pillars from the aurora borealis in California,” he writes. “That is kind of a rare thing. I’ve seen more pictures of wolves in CA than pictures of the aurora.” Credit: Dan McBride

The aurora pinnacled right up to the zenith and then spilled over into the southern sky with throbbing, amorphous patches of light across constellations rarely tainted by aurora like Ophiuchus and Aquila. Today, I’ve received photos from two localities where auroras are very rare: the Sacramento area in California and central Arizona at latitude +34°North.

A coronal mass ejection or CME from the sun on May 23 was the source of this weekend’s aurora. CMEs are massive but dilute clouds of subatomic particles — protons and electrons — blasted from the sun’s corona. The material can link into Earth’s magnetic field, follow the lines of magnetic energy down into the upper atmosphere and stimulate atoms to emit light: the aurora! Credit: NASA/ESA

A coronal mass ejection from the sun on May 23 arrived yesterday evening and triggered all the excitement. At peak, the geomagnetic storm topped out with a Kp of 7, making  it a G3 or strong storm. G3s can affect shortwave radio communications and send auroras as far south as Illinois and Oregon. Well, this storm certainly did better than that. I observed from home and from a quiet road on the most pleasant spring night imaginable with frogs a courtin’ and sweet breezes fluttering the new leaves.

Chris Schur of Payson, Arizona saw and photographed this green aurora low in the northern sky last night. This was when it appeared brightest at 11:20 p.m. local time (1:20 a.m. CDT). Schur observed both pink and green-hued auroras. Credit: Chris Schur

Occasional clouds tried to mess up the scene, but those of us in northern Minnesota waited them out. Nature provided even if it meant staying up late. No problem. I got out of bed happy and hungry at 9 and look forward to auroral leftovers tonight. The current forecast predicts a G1 or minor storm with the northern lights most likely confined to the northern states. But you never know. Take a look no matter where you are tonight.

2 Responses

  1. Horace Smith

    After submitting my previous comment I saw a nice discussion of the phenomenon on the Great Lakes Aurora Hunters facebook page. That site has nice time-lapse photography by Tim Wenzel. It has been argued that it was a moving auroral substorm, photographed from a different angle in Iowa:

    1. astrobob

      Hi Horace,

      That’s a beautiful sequence with the little picket-fence rays. Thanks for sharing it!

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