May 10, 2024 - Mountain Snow, Foothills "Thunderslush" and Aurora Borealis (Northern Lights), Colorado

by John Farley

This turned out to be quite an exciting day, as I witnessed snow in the San Juan Mountains, a thunderstorm with mixed winter precipitation ("Thunderslush") in the foothills closer to home, and a display of the Aurora Borealis (northern lights), all of it within 45 minutes or less of my home in Pagosa Springs, CO. And even caught a fish in the middle of all of it. Here is my detailed account:

1. Mountain Snow

I decided around mid-day to head up to the Wolf Creek area to see if I could catch some thundersnow. Convection was occurring south of Pagosa Springs, with a number of lightning strikes along US 84 southeast of town. With the storm moving northeast, I thought there could be some chance of thundersnow in the mountains, although it did look like the most intense part of the storm might pass south of Wolf Creek Pass. I considered going up one of the unpaved roads that go east from US 84, but did not, because I was concerned about the condition of the roads, how far they would be open up into the mountains (winter closures are still in effect for some of the Forest Service roads in the mountains), and the fact that if I did that, I would quickly lose any ability to keep up with the storm as it moved farther up into and over the mountains. So instead, I went up US 160 to the Wolf Creek Ski Area. Looking at the storms as I drove toward the mountains, it was evident that the snow level was pretty low, probably around 9,000 feet at the most, well below pass level. It was snowing when I got there, and as you can see in this picture, the ski area looked a lot like it does in the heart of the ski season:

Still looked very skiable, in fact, despite now being a month past the end of Wolf Creek's ski season. I moved down to the far end of the lower parking lot, to get a better view to the southeast and to get farther from road noise. Gradually with time, the snow increased, and became quite heavy for a while:

It was very pretty with the fresh snow on the trees - I'll take a view like that any time of year - but there was no thunder. By the time the picture just above was taken, it was snowing so hard that you could no longer see the ski runs - just a very fuzzy view of the base lodges. Later, when I got home, I looked at the lightning tracker and saw that there had been one strike in the snow around 15 miles south of the ski area - much too far away to get any thunder at the ski area. While I was there, I would estimate that it snowed up to a half inch, but it did not accumulate much on pavement and coming back, US 160 was just slushy between the ski area and the pass and just wet once you got much west of the pass. It had, however, been plowed due to earlier snow.

2. Foothills "Thunderslush"

When I got home, the skies had cleared and it did not look like any more storms were going up in the short term, so I decided to return to my original plan of going fishing at Lake Pagosa if it was not stormy. And I caught a nice crappie. But it was not too long before a new convective shower formed to the southwest, gradually intensifying as it moved closer. And as you can see in this picture, the p-type was snow or graupel (snow pellets) most of the way from the cloud base to the ground:

The lighter area under the precipitation, close to the ground, is the level at which it changed from mainly frozen precipitation to rain. So not making it to the ground as snow or graupel yet, but it might as it moved up into higher elevations. And there were a couple rumbles of thunder. So I decided to scrap fishing and make it a thundersnow chase. The heaviest of the core would pass somewhere northwest of my location, and Piedra Road, which I was right next to, goes northwest up into higher elevations close to 8,000 feet. I headed up that way, stopping once in a place close to where I should have stayed (Piedra Road and North Pagosa Blvd.). Got out, heard thunder, and thought it was still passing northwest of there (it was not) and went a couple miles farther northwest. There, I realized that the track of the core was going to take it south of that location, so I doubled back to a high spot southeast of Lake Hatcher. I set up for video, and soon got my favorite type of oddball precipitation, what I call "thunderslush" - winter precipitation mixed with rain, with thunder. Started out a mix of rain and graupel, may have briefly gone to mainly rain, then to a mix of rain, graupel, and wet snow - and thunder! Here is my video:

Thunderslush video:

At the very end, just after the thunder, it went to nearly all graupel/snow pellets, and then it was over and the sky began to clear as the storm continued northeast. When I got back down near home, there was a nice view of the retreating storm:

When I got home, it still looked pretty electrically active on the lightning tracker, which also confirmed there had been lots of electrical activity all around the Pagosa Springs area. My wife said there had been a lot of thunder at the house, but she thought just rain, not graupel or snow. These confirmed what I thought, which was that there had probably been quite a bit of thunder I did not hear when I was driving.

3. Aurora Borealis (Northern Lights)

It had been a pretty exciting day already, but the excitement was not over yet. I knew that there was a chance of seeing the Aurora Borealis (northern lights) as far south as Pagosa Springs, if it was clear enough to see them. They had already been visible there several times in the past year, during the current active solar cycle, but I missed them each time because I did not hear anything about it until they were over. (I had seen them many times growing up in Iowa and a few times as an adult living in the St. Louis area, but never in Pagosa Springs. And I had never successfully photographed them, except once through the window of an airplane with a camera that was not really up to the task, on the way home from a trip to Norway.) This time, though, the possibility of an aurora was well-advertised, so I was occasionally checking an online aurora tracker as well as news reports. Around 8:45, I noticed the half-hour forecast on the tracker had surged southward, so I decided to give it a try. The sky was far from totally clear, but it was not totally cloudy, either. I got to the boat ramp at Village Lake, which is in a dark area other than lights on the other side of the lake, around 9:15. (The lights on the other side of the lake were actually helpful for focusing the camera, and not bright enough to really interfere with viewing the aurora.) It was evident when I got there that, although there were far more clouds than ideal, the sky through the openings in the clouds was noticeably brighter looking due north than the clear sky in any other directions. And at that time, due north was easy to determine because there was a view of the Big Dipper and North Star, though they later became hidden by clouds. So I started to take pictures, and got this on my very first one:

Looking at it on the screen of my camera, I was a bit perplexed because it was much more colorful than what I could see with my eyes. I later learned that this is because the human eye is not as good as a camera at detecting color in low light, such as auroras near the horizon at lower latitudes. I should have remembered this from photographing a comet a few years ago and realized the same thing was going on, but at first I did not. Just before I took the picture above, while I was still getting set up, there had been an even brighter area visible through a narrow opening in the clouds below where the pink/purple colors are in the picture above, but by the time I was ready to take pictures, the opening in the clouds there had mostly closed. One thing I like about this picture is that I managed to capture a vertical beam of light in the aurora. I had not noticed that viewing it with the naked eye. This picture was taken at F/5.6, ISO 6400, 10 second exposure. No adjustments to color or brightness.

The clouds continued to move northeast, as had been the case all day, and the opening through which I took the picture above narrowed and shifted closer to the northern horizon. That allowed a somewhat different view of the aurora, capturing the pink/purple higher in the sky with a more greenish color closer to the horizon:

This is something that was evident in many pictures of the aurora that I later saw online, particularly ones taken at lower latitudes. I am sure this would have been much more evident with fully clear skies, but I had to work with the skies I had. All in all, I was pretty happy with my aurora photography efforts. In both of these pictures, but particularly the second one, note the reflection of the pink/purple colors of the aurora on the water near the far side of the lake, where there was a slight ripple on the water. I went back out and tried again around 11:30, but by then, clouds were completely hiding the northern sky, so I called an end to a long but very exciting day. And try to get some sleep ahead of the next day, which also turned out to be pretty exciting.

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