Tuesday, December 24, 2013

Arctic Cold And The Frost Line

frost line depth map New YorkWinter seems to have come early to the Adirondacks, as below zero temperatures and periodic bouts of measureable snowfall have been a part of our weather pattern since the last few weeks of November. The arctic air that has regularly swept across the region has made a sizeable dent in everyone’s wood pile, placed a strain on car batteries and forced many to wear Christmas sweaters on a daily basis.

The intense cold has also pushed the frost line down in numerous spots, which greatly impacts the existence of those creatures that attempt to survive this season by burrowing into the soil. It is difficult to determine how deep the frost line has advanced, as this critical feature of the winter environment varies greatly from one spot to another.

The frost line is the depth at which water molecules suspended in the soil freeze, creating a solid, impenetrable layer of material that is fatal to many lower forms of life. This is why many organisms sensitive to freezing conditions try to get as far down into the dirt as possible during the autumn so as to remain below this hardened zone of ice, sand and other soil components.

Unlike the layer of ice that forms on a body of water, the frost line is not uniformly thick. Rather, the thickness of this surface barrier varies greatly, depending on the localized surface features in the area and on the amount of snow that has accumulated at that site. In wind swept locations, such as along the windward shore of a lake or pond, the top of a mountain ridge, or an open meadow regularly buffeted by strong breezes, snow depth is often substantially less than in sheltered spots, thereby allowing the cold to more easily penetrate the ground. In places where snow frequently drifts, the insulating effect of this powdery material can prevent the soil’s heat from radiating to the atmosphere, which helps maintain only a shallow layer of frost in the ground.

While fluffy snow is ideal insulation, this light weight crystalline precipitation may fail to reach the ground in dense stands of conifers. At this time of year, evergreen trees, with their boughs laden with a thick white coating, are the picture of a winter wonderland, however a hike through a softwood forest reveals that the amount of snow on the ground is substantially less than in a close by stand of open hardwoods. Also, because many evergreen woodlands develop in lowland locations where cold air settles, the frost line can be much deeper in these snow covered woods compared to other areas.

It is believed by some naturalists that creatures sensitive to freezing temperatures instinctively seek out settings in which the frost line is not likely to develop very deep as they prepare for the coming winter. Most wasps, ants, and native species of bees, along with many types of beetles and grubs, worms and other invertebrates, some forms of salamanders and a few types of snakes have not evolved the cold hardy body chemistry capable of surviving freezing temperatures, like the snow flea, the wood frog, spring peeper and garter snake.

Animals intolerant of freezing conditions can sometimes survive in the Adirondacks by burrowing into south facing slopes where snow often drifts, causing the frost line to remain close to the surface. Depressions in the ground where dead leaves accumulate in autumn create an insulating layer of organic debris that can limit the frost from penetrating too far, as can the soil beneath a massive, decomposing log. In residential settings, the soil around the foundation of a house often remains just above freezing throughout the winter regardless of snow and temperature conditions. This is why there is always mole activity during the winter near my house, as this small subterranean mammal inevitably feasts on the collection of bugs lured to the thawed dirt just outside my basement.

Just as there is a world of activity beneath the surface of the snow in winter, there is a similar zone of life under the frost line throughout the winter. Because of the extreme difficulty in gaining information on the abundance of the life forms that occupy this area, their movements during this season, and the dynamics that occurs between these organisms, not much is known about life below the frost line. It is often a challenge to gain information on the daily habits of many creatures that live above ground, especially those that shy away from human presence. Gathering data on the interactions that routinely occur below the soil’s surface is even more difficult, and when the top layer of soil develops a concrete hardness, that challenge becomes even more impossible. Yet there are a few researchers that are gaining some insight into the working of nature below ground at this time of year.

The soil is an integral part of our natural world and understanding what occurs within it and below it, even during winter, is important in getting a more complete picture of nature here in the Adirondacks.

 


Tom Kalinowski

Tom Kalinowski is an avid outdoor enthusiast who taught field biology and ecology at Saranac Lake High School for 33 years. He has written numerous articles on natural history for Adirondack Life, The Conservationist, and Adirondack Explorer magazines and a weekly nature column for the Lake Placid News. In addition, Tom’s books, An Adirondack Almanac, and his most recent work entitled Adirondack Nature Notes, focuses on various events that occur among the region’s flora and fauna during very specific times of the calendar year. He also spends time photographing wildlife. Tom’s pictures have appeared in various publications across the New York State.




8 Responses

  1. Tom Vawter says:

    Nicely written article on an interesting topic, Tom. Thanks.

  2. jay says:

    Where are all the global warming fools?

    • John Warren John Warren says:

      Yeah, because one weather event completely disproves the opinion of the vast majority of climate scientists and a half century of research.

    • Tom Kalinowski Tom Kalinowski says:

      Hi Jay: Please be aware that the Adirondacks are still running over 2 degrees above normal for the year. Also, the weather in this small section of the globe should never be confused with the overall climate of the planet. Even though we may be colder for the month, there are many locations, such as in many regions of Alaska that are substantially warmer than at anytime in the past. (Check out the weather summary for Barrow, Alaska for this December!!)

  3. mary R says:

    Moles, voles always seeem to have them around the foundation for the signs are always there in the Spring. Is the type of soil also a factor, must be.The richer the soil the more moles, voles, besides the foundation as a factor.

  4. Tom Kalinowski Tom Kalinowski says:

    Hi Mary: The type of soil, as well as the moisture content of the soil are factors that help determine the soil fauna. With more invertebrates in the dirt, the chances are good that there will be more mole activity. Voles feed mainly on plant matter, and around my house, it is the concentration of flower bulbs that determines that vole activity around the foundation.

  5. Charlie S says:

    You’re wasting your breath Tom.Some people will never get past their narrow,short-sighted,limited view of things no matter how much truth you put to them.
    Interesting read.Bugs,and all of the earth’s critters,are fascinating and play a very important role in the preservation of the earths eco-systems.Tell that to a capitalists!

  6. Mike Prescott Mike says:

    Jay, we are talking Global Climate Change, not isolated, individual events. Take a look at the Global research over years, not just one month in the Adirondacks.. It is Global warming, and Global climate change. Tom’s article is well researched, well thought out, and well written. We need to think Globably, not in an isolated vacuume. But, of course what can you do with those who do not think ?