It has been one of those weeks — sitting indoors, in windowless rooms, arguing about esoterica, tying up millions of brain cells storing and manipulating endless rows of numbers in government budget documents.
Therefore, it is purely my fault the record-breaking stretch of ice, snow and extreme subzero temperatures has broken. Outside, although I cannot see it, the sky is blue, the snow is melting, and the temperature is nearing a balmy 40 degrees. Enjoy it while you can because I must advise you that, by the time you read this, I am going to have an entire day at home to myself. Therefore, I presume the temperatures will plummet and the skies will open with all sorts of unpleasant precipitation.
The so-called “January thaw” is what is called a singularity. A singularity is a climate event that happens more often than not at a particular time of year. I am sure we can all remember years when January stayed frozen all the way through and yet we still look forward to a brief respite and most years get our wish. It may be the time we give the barns and coops a midwinter cleaning, go to the woods to bring out the rest of the firewood, work on maple lines, check the bee hives, or let the livestock out into the big pasture for some exercise.
The January thaw most often occurs around the third week of the new year although it can be earlier, like this year, or not happen until early February. It has also been happening for as long as there have been records and appears in many aboriginal tales. The father of American conservation, Aldo Leopold, wrote about the January thaw in his seminal wildlife management work, A Sand County Almanac: “Each year, after the midwinter blizzards, there comes a night of thaw when the tinkle of dripping water is heard in the land. It brings strange stirrings, not only to creatures abed for the night, but to some who have been asleep for the winter.”
A significant break in the weather makes a huge difference to many species and a number of them in the northern areas depend on it. The most obvious benefit is to the various predator species. A switch to a subnivean lifestyle allows many small mammals to not only avoid predators in their hidden snow tunnels but enables them to travel great distances, accessing more food resources. This nutritional base allows breeding and some pretty significant population increases as long as the snow cover holds.
Predators like foxes, hawks and owls, especially the juveniles facing their first winter, are most likely to experience starvation during the weeks following the solstice, especially if the snow is deep. There is a wealth of food, but it is buried under feet of snow, detectable only by hearing. The great plunges into the snow by predators makes great TV footage but results in a successful capture in very few instances. A snow melt exposing the small mammals can be an actual lifesaver for predators and may even allow them to replenish fat reserves to help survive to spring when the snow returns.
Great horned owls benefit particularly from the break in the weather. The great noise and activity by the large predators in the weeks leading to Christmas are not the “owls singing Christmas carols,” as some have written. In fact, their mating and nesting is beginning in the first weeks of January. A warm week or two allows the female to conserve energy while incubating and allows the male to catch more prey to feed her as she broods.
The snow in front of my bee hives is thoroughly stained with yellow spots during the January thaw. The bees, confined by the cold for weeks, take the opportunity to make a “cleansing flight” and expel feces accumulated up to that point. Interestingly, a number of the animals that do not actually hibernate but become torpid during the cold benefit greatly from a break in the weather for similar reasons. While these mammals may not have eaten much and thus are not out and about for the same reason as the bees, their muscles and tissues have accumulated toxins and by-products of metabolism of fat, which are best expelled through a bit of exercise. Therefore we find many skunks, raccoons and squirrels out taking a walk-about.
The nice weather can be a mixed blessing for the deer. In the deep snow, deer tend to be energy reservoirs. Survival depends on staying still, nourished by their summer fat stores, and using as little energy as possible. In the traditional deer “yards,” this often results in increasingly small paths and trails confining them. A brief melt allows them some more mobility to increase the yard size again so they can seek out the warmer spots as the day length and sun angle changes.
The downside is that winter often returns quite precipitously. What sometimes happens is the soft snow refreezes with a strong icy crust. A thick crust virtually immobilizes a hoofed animal — they can neither break through nor walk on the crust. An animal with padded feet such as a coyote or, worse yet, domestic dog finds the crust a perfect highway and they run at will. There have been cases of the entire population of a deeryard being wiped out overnight under crust conditions. This is sometimes not that much of a benefit to the predator either. While they typically kill until nothing is immediately available, their actual consumption may be limited to a single carcass, the rest rendered useless by freezing and becoming covered with deep snow.
While we may not as readily see it, the trees and plants also reap a benefit from a freeze-thaw-freeze cycle. Contrary to popular belief, they are in no danger of being “tricked” into producing buds to subsequently freeze off. They produced large amounts of abscisic acid in the fall; this is involved in leaf drop. The levels of abscisic acid drop naturally over the winter, replaced by gibberellic acid, which allows bud growth when the length of day has increased enough.
However, the benefit to plants comes from activities in the soil itself. Neither long periods of cold nor long periods of warmth do the best job of assisting the bacteria in breaking down residues to a form that the plant can use. It is the change from cold to warm that speeds this process so having a January thaw makes many more nutrients available to the plants when growth starts in spring.
A January thaw is quite a wondrous thing — wish I could have seen it.