Sitka Nature

Graupel is a type of snow that forms when snow flakes fall through parts of the atmosphere that have supercooled water droplets. Instead of maintaining the form of flat snow flakes and/or elongated snow crystals, the supercooled water condenses as a rime on the surface that results in a pellet shape. Superficially, graupel looks a bit like hail, and many people call it that, but hail is a solid ball of ice that forms in repeated freezing/thawing cycles as water/ice is subject to updrafts and downdrafts in thunderstorms. With a little extra attention, it’s not hard to identify graupel from its less solid feel and slightly fuzzy appearance.

In Sitka, graupel is a fairly common form of precipitation from at least late fall through spring. I remember as a kid noticing that it seemed to fall, sometimes quite heavily, and then shortly after, a more traditional snow would begin. At this point, I’m not sure how strong that relationship is, but it did hold this week. We had a fair amount of graupel Saturday, especially in the afternoon and evening, with snow developing later in the evening and falling through much of the night. Perhaps the conditions that prevail as a front moves through are conducive to graupel formation, with snow falling after the passage of the front.

Salmon Lake trail follows Salmon Creek up from the end of Silver Bay to Salmon Lake, and then further on up the valley, ultimately branching with the main current trail going over to Redoubt Lake Cabin, and a historical trail that leads up to the Lucky Chance mines (though I’ve been told it’s difficult to find and follow in many locations). Last Sunday I had the opportunity to go out to the trail and hike around for a bit.

Given the early winter season and a blanket of snow covering the trees and much of the ground, there was not too much to look at in terms of plants, but the scenery was quite stunning. There were deer tracks around, but I never saw a deer. A mink showed up on along the frozen lake shore, and there were several species of birds, including American Dipper, Brown Creepers, Hairy Woodpeckers, Mallards, Golden-crowned Kinglets, and a late Hermit Thrush.

The valley bottom forest structure seems much different than I am used to seeing in Indian River Valley (the place with which I have the most familiarity). The wide spacing of trees and predominance of Sitka Spruce are particularly notable. I’m not sure what might be the underlying reason for these differences.

Salmon Lake was covered in a thin layer of frozen slush/ice. It might have been an inch thick, not nearly enough to support my weight, but a mink that scampered along the ice near the shore seemed to be in no danger of breaking through. At the inflow, there was still a patch of open water above the main body of the lake.

In clearings above the lake, both the upper lake sedge marsh/meadow, and muskegs further up, the snow was 1-1.5 feet deep or so. It was not as deep in the woods, nor the openings at the edge of the estuary below the lake.

This was only my second trip to Salmon Lake, the first being in October 2007. Neither trip has been especially well timed for seeing how the distribution of herbaceous plants growing in the valley may differ from other locations, but I do hope to get back for a future visit to look into it a bit more.

While out there, I also learned that owls (probably Western Screech-owls) are a frequent visitor to the NSRAA weir site, and toads are also not hard to find.

More Salmon Lake Trail photos.

Most of today’s photos were take on a trip to Salmon Lake. The exception is a picture of The Sisters at Sunrise.

[View with PicLens]

I had heard this year was going to be an El Nino year, which seems to correspond to relatively mild winters in Sitka, so it was interesting to see winter season getting started relatively early this year, with snow beginning to fall last week. In fact, there is an El Nino developing in equatorial Pacific Ocean, but apparently in the Pacific Northwest, at least, El Nino impacts tend to be strongest later in winter.

I had ibuttons I wanted to place for a project on temperature variation I’m working on, so I took a couple of hours to hike up Indian River. There was not too much snow in the woods, but in the openings it was at least a foot deep. Temperatures are supposed to rise into the 40s this week, so the snow may not last long, however.

It was pretty quiet overall, but I did hear some Ravens and Golden-crowned Kinglets. I also saw a couple of Brown Creepers and a Varied Thrush. Lots of deer tracks, but I did not see any deer.