SIOUX CITY, Iowa (KCAU) – Many lucky stargazers were treated to a rare sight Sunday night. For those lucky enough to find a dark spot, away from substantial light pollution, the Aurora Borealis, more commonly referred to as the “Northern Lights,” put on quite the show and provided ample opportunity to catch the phenomena on camera, both in stunning photos and videos.
Typically most commonly observed in higher latitudes, in areas like Alaska, Canada, and parts of Greenland, especially during the winter months, the Aurora Borealis is caused by electrons and protons ejected out of the sun via solar winds.
These charged particles end up entering Earth’s atmosphere and collide with mostly, nitrogen and oxygen molecules. Upon colliding with the atmosphere, they absorb energy which is then released as light energy in order to return to their normal positively (protons) or negatively (electrons) charged states.
This light is seen as the aurora along the magnetic northern and southern poles at the electrons travels along the magnetosphere.
The lowest extent of the Northern Lights is usually around 60 miles above Earth’s surface and typically extends as high as 120 to 200 miles, occasionally to 350 miles, or the level at which the International Space Station flies.
However, the Aurora isn’t visible in just any conditions. As we’ve established, best viewing opportunities are commonly found farther north towards the poles.
Skies will need to be clear or mostly clear and you’ll have to get away from city lights/light pollution for optimal viewing. Another factor to think about is season. In the summer, the high latitudes where the Aurora is usually found are in the period where they experience nearly constant daylight. Therefore, you might assume winter, when they have near constant darkness would be optimal for viewing, but actually, the spring and fall equinoxes when larger geomagnetic storms tend to occur.
Sometimes, if a geomagnetic storm is strong enough, which was the case Sunday night, the Aurora/Northern Lights can be seen further south, in lower latitudes. Geomagnetic activity is driven by solar activity and coronal holes.
In Sunday night’s case, a solar flare was recorded by NASA’s Solar Dynamics Observatory on Friday. This was followed up by coronal mass ejection (solar plasma, charged particles, and magnetism), which made impact with Earth’s magnetic field Sunday afternoon. This ejection and collision resulted in a severe geomagnetic storm with planetary K indexes or Kp indices, which are used to indicate geomagnetic activity, between 5-6. This resulted in the southern viewing extent moving much farther south than usual.
The forecasted southern extent of viewing for Sunday night was through the northern half of the United States, including, through much of Iowa and here in Siouxland. However, this ended up extending much further south than forecasted.
Locations as far south as Arizona, Arkansas, and Texas were able to catch a glimpse of the breathtaking views and dancing lights of the Aurora Borealis.
Monday night could provide viewing opportunities once again in areas that saw the Aurora last night, however, mostly cloudy skies forecasted across Siouxland for tonight look to put a damper on viewing locally.