3.30.01 Rapid City, SD

3.30.01
Rapid City, South Dakota
(Geomagnetic Storm)

A major aurora event occurred this evening with observers witnessing beautiful displays as far south as southern California and Arizona. I first observed the aurora around 9 pm. It started as a green diffuse glow from the northern horizon up to 20° elevation. Red beams and rays developed from 20° to 90° elevation. The red aurora was just spectacular. I photographed the event for about an hour before the glow became more diffuse and continued to spread southward to about 20° above the southern horizon. Clouds later moved in to block the view of this spectacular event.

The aurora event was caused by the arrival of a coronal mass ejection that buffeted our magnetosphere around 6 pm 3/30/01 (0100 UTC - 3/31/01). An X-Class solar flare emanating from a large sunspot region started this process and produced an S1 radiation storm. A coronal mass ejection soon followed and this ejection of solar plasma took a few days to reach the earth. Unlike the solar flare which emits intense electromagnetic radiation that reaches our planet in about 15 minutes, CMEs travel from 500 to 1500 km/s and take 2-3 days to arrive.

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All times are MDT

	915 pm (0415 UTC - 3/31/01) View looking north from Carriage Hills in west Rapid City.
	930 pm (0430 UTC - 3/31/01) View looking north-northwest from Carriage Hills in west Rapid City. Clouds where starting to interfere with the light show.