Sunshine melts snow, but it also turns it into vapor which tends to rise and later condense into clouds. At McCall Glacier, we have the neat opportunity of watching this happen before our eyes. Today was a sunny, clear day, at least on the synoptic scale of regional weather. But once the sun rose high enough to increase its energy flux to the surface, it began creating clouds locally. Because our camp sits within a bowl shaped valley, we can watch the sun as it swings from the east to the west in a big circle and heats up the backside of our valley walls. So when the sun is in the east, we see clouds forming directly behind our eastern valley wall, and as it swings to the south we see clouds there but not in the east, and so on. To better visualize this, I took a sequence of panoramas throughout the day, as well as setup a time-lapse camera to show the processes.


(Click on the panorama and drag to look around, press Shift to zoom in, Command (Mac) or Control (PC) to zoom out.) Enlarge this panorama


East clouds. Enlarge this panorama


South clouds. Enlarge this panorama


West clouds. Enlarge this panorama


North clouds. Enlarge this panorama


Unfortunately I mis-programmed the camera so it ended early, but it gives the sense of local cloud formation.

This process of sun vaporizing snow can create more than just clouds – sometimes it creates new snowfall and sometimes it just stays a clear sunny day. The difference is likely to do with air temperature, which controls how much vapor the air can carry before it must condense. For example, on several bright sunny days this April, instead of forming poofy clouds like today, the vapor condensed directly into snow, skipping the liquid stage, such that we had blue skies and snow at the same time, without any intervening clouds. That is, snow was falling on us, but there were no clouds, just blue skies and sun. We had several days of this during our camp move from the upper cirque to the ablation area. Jason and I began thinking of ways to try to collect the snow and isotopically compare it to that on the hillslopes, but it would be tricky business to do correctly and we were quickly distracted by other tasks. In terms of glacier mass balance, it’s probably a pretty minor process, but it is still a mechanism by which mass (in the case snow) moves from the hillslopes onto the glacier. Whether sunshine creates snow, clouds, or invisible vapor, I think this movement of water is still an interesting process, and not one that is probably well studied.

In between taking cloud panoramas, I went halfway up to the upper cirque and found a new photo spot. There are several ridges that descend to the ice surface, all of which used to hold small tributary glaciers 100 years ago. As the ridges become exposed, they become somewhat good places for photography. Apparently I wasn’t the first to discover this, as the one I hiked up to had been used as a survey station in the 1970s, as the mark and foil used to locate it on air-photos was still visible. Though it was not far above the current ice surface, it was a still a challenge to reach because of the large, loose rocks surrounding it. Here giant slabs of bedrock were detaching and sliding off the outcrop on their own. But once on top, it was a comfortable place to work, and I took several high resolution panoramas.


Enlarge this panorama

[A note on panoramic image quality. Because I’m in the field trying to do many things and trying to minimize time in front of a computer and maximize field time, I’m skimping substantially on panoramic photo quality. Though I shoot in RAW mode, I also create a smaller JPG preview at the same time, and I just use that for these panoramas. When stitching, there are many little tweaks that could still be done, but I try to put the least work into as possible to create a decent image. So I consider all of these just preview panoramas, and when I return from the field in September I will recreate the best ones to a higher standard. Also, I’m not stitching or posting my gigapixel panoramas here, which are substantially higher resolution and show incredible detail. You can see about a hundred panoramas I made last year here. These were all from my first season trying to make high quality panoramas, so you may also find a number of errors, and I’ve tried to point out many of these myself in the associated text to help improve my technique and remind me what not to do in the future. In any case, what’s posted in these blogs are not the final versions, and I will post a note here once I start putting the final ones online.]


Turner and T Rex take a bath.