A solar storm forecast to take place on Thursday is set to bring the aurora borealis, or Northern Lights, into the sky of 17 states as it dips much farther south than is typical.
Update: As Thursday night approaches, newer data suggests that the original estimation of aurora visibility was a bit too cavalier, and the number of states set to have visibility has decreased, per CBS News. Original story below.
2023 has been a particularly active year for solar storms and a forecast from the Geophysical Institute at the University of Alaska at Fairbanks expects that 17 states will see aurora activity on Thursday: Alaska, Oregon, Washington, Idaho, Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, Michigan, New York, New Hampshire, Vermont, Indiana, Maine, and Maryland. Of course, that means Canada is also set to see the aurora even as far south as Vancouver.
Phys reports that the lights should be visible over major cities, including Milwaukee, Helena, Salem, Boise, Cheyenne Annapolis, and Indianapolis.
The activity is expected to be a Kp 5 on Wednesday and increase to a Kp 6 by Thursday. These numbers are based on the K-index, which is used to characterize the magnitude of geomagnetic storms. For reference, a Kp of 0 to 2 indicates dim, low activity. A Kp of 3 to 5 means it will become brighter and there will be more auroral activity such as visible motion and formations. At a level of 6 or 7, the aurora is quite bright and active. The highest the Kp scale goes is 9.
The moon phase is also fortuitous, as it is a “last quarter” moon and won’t be particularly bright.
While it isn’t the most powerful the aurora has been this year, it is significant and will give Americans in northern states the chance to see an event they might otherwise never be able to appreciate.
The last time an aurora dipped down low enough to provide a visual treat to northern states was in late April. At that time, the aurora lit up the skies above Yellowstone National Park.
While impressive, that wasn’t even the most impressive solar storm in 2023. On March 23, the activity was so abundant that the northern lights were visible as far south as New Mexico and Arizona, providing photographers with a stunning night sky that is exceptionally rare for the region.
For anyone who missed those last two events, this week’s storm is another opportunity to get the shot — there is no telling how many more times it will happen.
Header image: Photo by Kristi Odom