What a difference a day makes. Yesterday morning Dan and I took Raven and walked down the lake, across the ice. The entire lake was frozen solid, shore to shore, with a thin layer of soft, dusty snow settled on top of it. We could probably have taken our skates if we wanted. This morning the weather was warmer, and it rained all day. Instead of a thin layer of snow there was a layer of water sitting on the ice, reflecting the sky and the skeletons of the trees on the opposite shore. The riverbed channel in the middle of the lake was starting to thaw out and thin.
This photo is from yesterday, when the frozen lake was an open, pristine expanse of snow, untouched, crisp and clean. These are my favourite snowscapes, broad, open spaces, newly fallen snow with no tracks or blemishes yet. Thick, wet snow outlining the branches of the trees is a very close second. It’s been a while since I’ve seen the lake from this point of view, not since we were able to take the boat out.
We noticed this while we were out. The thing that caught my eye was actually the change in colour of the ice where Dan’s footsteps had scuffed away the snow. Most of the lake is covered in cloudy white ice, but for a couple of steps the ice was clear and dark. Taking a closer look I could see that there was a noticeable track in the ice going back to the shore, and, following its length, a beaver lodge at the shore’s edge. There are several such lodges along the shores of the lake. I’m not sure how many pairs of beavers there are here, and therefore how many of these lodges are occupied, but it appeared that this one has active residents. The change in colour of the ice was due to the activity of the beavers as the water was freezing, keeping a narrow channel open as they moved to and from the lodge. Probably most of the ice began to freeze overnight, when beavers are more active, and then once they retired in the morning their channel finally got a chance to close up.
I tend to think of beavers as being semi-hibernators over the winter, but actually they remain active all through the cold months. In the fall they build up a substantial larder of branches and small tree trunks, stored underwater where they can access it from the lodge even when the water surface is frozen solid. Beaver activity peaks in the spring and fall; in the spring they are repairing their structures that may have sustained damage in the harsh winter conditions, in the fall they are stockpiling food for the winter. Beavers can hold their breath for up to 20 minutes, but like all land-dwellers must come up for air at some point. Sometimes the water level will drop after the ice has formed, creating an air pocket between the two, or if the ice is thin enough the beaver may be able to create a breathing hole, but more often it will need to return to its lodge. To provide air circulation and allow fresh air to enter the lodge, beavers don’t pack mud on to the top of the dome, which creates a sort of ventilation “shaft”. I didn’t look for it yesterday, but one website suggests if you look closely on a cold day you can see the wisps of warm, moist air from the beavers within escaping from the little gaps in the peak of the lodge.