Northern Lights visit the Tri-State Region

Aurora Borealis Observed on December 14, 2006

1. Event Overview

An aurora borealis occurred during the overnight hours of December 14, 2006, visible in the United States as far south as Oklahoma. The tri-state region was no exception as partly cloudy skies allowed for great viewing. Recent major solar flares associated with an active sunspot region (Region 930) on the Sun were responsible for producing the severe geomagnetic storm. Additional significant solar flares are expected for the several days.

Fig. 1. Sunspot Region 930 on the Sun. Image courtesy SOHO /MDI.

2. Pictures

The following picture was taken 12 miles north of Goodland, Kansas at 7:20 pm MDT (0220 UTC). The colors began immediately following sunset as several discrete patches of white followed by bright greens and dull reds. By 8:30 pm MDT the aurora peaked leaving the remainder of the night with a dull green glow, location 4 degrees above the northern horizon. Note the off white "pillars” in the photo. The pillars were observed to move rapidly east to west across the northern sky. Mouse click on the images to view full size. Photo courtesy A. Pietrycha.


3. Data

Values of an index to measure geomagnetic activity, known as the Kp index, rapidly increased over the region during the morning of December 14, 2006. By 5 pm MDT (00 UTC) indices peaked at eight and held through 11 pm MDT. For the magnetic latitude of Goodland, an optimal Kp value to view the aurora is nine. Such levels foster spectacular auroras over the tri-state region. The figure on the right shows the trend in the Kp index. For more information on what the Kp index is, and how to determine optimal viewing conditions for your location, visit the SEC website.

Fig. 2. A plot spanning the overnight hours of 14 December 2006, containing the estimated planetary K-index. K-indices of 5 or greater indicate storm-level geomagnetic activity. Image courtesy SEC.


The figure to the right shows the extent and position of the auroral oval from the North Pole; valid near the time the photos above were taken. The image is extrapolated from measurements obtained from the most recent polar pass of the NOAA POES satellite.

Fig. 3. Extent and position of the auroral oval valid 0112 UTC, 14 December 2006. Image courtsey SEC.


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