Aurora Borealis: 10–11 December 2025

Solar Max continues to produce auroras that are visible at low latitudes. The most recent occurred on the night of 10–11 December. Once again, I chose to shoot from Ashurst Lake because it has very good visibility to the north. This time, though, we did not venture out to the edge of the lake. Heavy rains in November (almost 5″) has resulted in wet soils that have not dried in the colder temperatures and low sun angles of December. No desire to sink in the mud!

Shooting from the parking lot was a good alternative but did not give the expansive reflections from the lake that I have enjoyed before.

The aurora substorm starts up to the northeast with numerous pillars visible.
The aurora substorm starts up to the northeast with numerous pillars visible.
The pillars move westward over the next few minutes. The North Star, Polaris, is highlighted here to give a sense of the low heights of these pillars.
The pillars move westward over the next few minutes. The North Star, Polaris, is highlighted here to give a sense of the low heights of these pillars.
The substorm subsided leaving just a faint glow to the north. A meteor (probably a Geminid) streaks across the sky with the aurora as a backdrop.
The substorm subsided leaving just a faint glow to the north. A meteor (probably a Geminid) streaks across the sky with the aurora as a backdrop.

This aurora was lower intensity and much more difficult to see than the event in November. In fact, we were unable to see it with the unaided eye. Reviewing the photo images after the event clearly showed there was a sub storm that lasted about 20 minutes. The peak heights of the pillars was much lower than we have seen before.

I have been learning how to use satellite data to forecast when these substorms might appear. Here is a plot of the data leading up to the substorm which occurred around 1918—1940 MST (0218—0240 UTC 11 December 2025). The vertical line shows when the substorm pillars first appeared in my photographs.

Solar wind data used to forecast the aurora substorm.
Solar wind data used to forecast the aurora substorm.

Images: Nikon D850, 17mm, f/2.8, ISO 3200, 15 seconds.