What The Heck Is That Light? Please Take A Guess.

I can’t figure this one out and I need your help.

While photographing Mt. Rainier and the stars overhead this last weekend (September 7th, to be exact), I noticed an odd light you can see in the image below. I say some goofy things but this, this at first looked like a flare because it kind of danced. But then we (I was with two photography clients who saw and photographed the same thing)noticed it moving sideways and not going out like a flare would. Plus it was orange, as depicted here.

What confounds me is that it wasn’t blinking as if it was going behind the trees, much as the cars on the road below were. It was slightly above the treeline and moving from right to left (East to West). There is no road that high (in the sky) and if it were back on the mountain, about a mile behind the treeline, then it would be moving very fast straight across ridges and gullies. It’s confounding.

Here’s the bigger view of what’s going on. This is a 10 minute exposure and has been edited, but I left the streak alone.

Now here is a 100% crop of the light trail. (Click photo for a larger version)

Lastly, I jacked up the Exposure setting in Lightroom to show more detail. As you can see, there is no road there and it ducks behind a few trees.

Does anyone have a plausible answer for what this is? I’m confounded. For reference, the bright fog on the right is Paradise.