February 1, 2026: The Deep Freeze

The deep freeze predicted for this week came through with a vengeance, starting off with of 15" of fabulously light snow on a cold Sunday night.  

The frigid temperatures that followed all through the week demonstrated a couple of physics lessons for us.  Tuesday night into Wednesday morning the atmosphere was clear, calm, and very dry (a dew point of -22 degrees).  The warmth of the earth was kept in place below the thick blanket of insulating snow, and 100% snow cover with no clouds to reflect back to earth what little heat was available above the snow pack, all conspired to allow intense radiational cooling to drop the temperature rapidly.  And with no wind to stir up the atmosphere, cold, dense air flowed right down to lake level.  The Lake Wicwas Weather Station recorded a low of -19.3 degrees that morning. 

Lake Wicwas Weather Station Data for January 28, 2026

Meanwhile, 50 feet higher in elevation on Corliss Hill, just a half mile from the lake, it was only -10.5 degrees.

Weather station on Corliss Hill

That's the coldest night we've had this year.  

A book titled "Winter World" [Bernd Heinrich, Harpers Collins, 2003] provided my second physics lesson.  I've mentioned previously the subnivean zone - the realm at the interface of the earth and the bottom of the snow pack - as well as some of the animals that safely reside there during the winter.  But I now learned why the temperature stays so close to 32 degrees there; it has to do with the physics of water as it melts and freezes.  Heat generated in the center of the earth rises up and melts snow at the bottom of the snowpack, which, as mentioned above, is a good insulator.  But as the season gets colder, the cold seeps down and starts to freeze that water.  

Heat from below melted this patch of snow.

But the process of water freezing is an exothermic process, meaning it gives off heat.  Why is that since it's getting colder?  Liquid water has a lot of kinetic energy - the motion of molecules moving around which keeps it liquid.  When water freezes, molecular motion slows dramatically, which is how it gets locked into solid crystals rather than flowing water.  

Liquid water in the area of the previous photo starts to freeze from exposure to radiational cooling.

But conservation of energy requires the kinetic energy to go somewhere, and it goes into thermal heat.  That heat warms up the subnivean zone under the insulating blanket of snow.  Conversely, during a stretch of warm weather, some ice melts, which now absorbs heat, thus lowering the temperature of the zone.  As Heinrich writes, 

Thus, as long as both ice and water exist side by side, they constitute a thermostat keeping temperatures constant.  Only the amount of ice and water vary, depending on the amount of heat loss or input.

The result is a nice stable environment for mice, moles, squirrels, spiders, and the larvae of insects such as butterflies and moths to spend the winter - the subnivean zone.  (niveus is the Latin word for snow.)

Humans might not appreciate long frigid stretches of cold, but it brings benefits that haven't been seen in quite a while.  One of the most important of these affects moose.  The moose population has been decimated by winter ticks which used to be killed off by cold temperatures, but for many years now, winters have been so warm that these ticks survive all winter.  Thousands of these ticks cling to a single moose and can drain enough blood from a even a full grown moose to kill it over the winter.  This stretch of cold should help the moose a lot.  Other benefits include killing off some of the invasive insects that have moved north into New Hampshire and are decimating our forests.  We might even get a reduction in the number of deer ticks and wood ticks that prey on other animals - including us.

The light, deep snow has made difficult travel for animals that live above the snow.  Not a single squirrel has made it to the feeders all week.  The bobcat with its large feet was sinking in enough to simply plow a path through the snow.

Moving off the lake it plowed a path through the woods before stopping for a well earned catnap under a hemlock tree.

Now, a week after the storm, it's been so cold that even today the snow is so light it feels like it fell just last night.  All week the skiing and snowshoeing has been great.  

Furthremore, the cold weather has allowed the Pond Hockey tournament to be held on Meredith Bay. 

It's quite a scene on the lake with hockey action surrounding you in every direction.

It's always good to root for the home team!

Giuseppe's takes on the Killer Beez

In between games the ice is swept clean to keep the action fast.

The women are definitely in the action as well.

With plenty of ice in the lake, a whole village has popped up and it will only grow this week as people arrive for next weekend's fishing derby.  

The hockey tournament continues through 2:00 today, so there's still time to check out the action.  Next weekend is the fishing derby, and based on the forecast, the sled dog races on February 13-15 should be good to go as well.

You can get right up close to watch the sled dog action.

Wicwas is often featured on the fishing derby leader board for both pickerel and black crappie.

There are so many ways to enjoy the winter season.  Cold temperatures and plentiful snow are providing a great start to 2026!

March 17, 2019: The Subnivean Zone

A friend recently mentioned that the raptors - owls and hawks included - are having a hard time getting food this year due to the deep snow which allows their primary food sources such as mice, voles, and red squirrels to take cover in a well fortified subnivean zone.  That may sound like the secret hideout of some evil creature from a Star Wars movie, but subnivean is a scientific term that comes from latin for "under" (sub) and "snow" (nives);  it refers to the narrow gap that forms between the forest floor and the bottom layer of snow.  [Much of the information here comes from the article "The Subnivean Zone:  Shelter in the snow" written by Barbara MacKay and published on December 26, 2014 in the Burlington (Vermont) Free Press .]

Subnivean Zone Illustration by Adelaide Tyrol from the above referenced article

As the early snows fall at the start of the season, the still-warm earth sublimates the bottom layer of snow which rises and condenses on the cooler surface above, then freezes, creating a sturdy ceiling that can hold up the winter's later snow.  Low plants also help to support this snow/ice roof.  It may only be an inch or so high, but that's enough to get things started, and the rodents will build intricate tunnels from there.  And it provides them everything they need - food from seeds and grasses on the ground, insulation from the cold of winter, and protection from predators.  This winter I have seen very few mice tracks up on top of the snow, which indicates to me they are fully satisfied down there under the snow.

Mouse tracks on the snow have been few and far between this winter

Usually fox can still access these animals using their strong sense of smell, and owls can track them down using incredibly sensitive hearing.  Both animals can attack through a reasonably thick layer of snow, but this year's repeated icing and deep snow have made these hideouts pretty much impregnable to all but the ermine.  (The ermine is slender enough to climb down the air holes into the subnivean zone, and eat to its heart content, sometimes taking over the area for itself.)  With all this in mind, I kept an eye out this week for signs of these secret hideouts.  I was able to find a couple, one under a large fallen limb and the other at the base of tree.

A classic entry hole to the subnivean zone

This one is a text-book subnivean den:  built on the southern side of a dark tree where the sun will help to keep things warm and melt some snow to provide a bit of water.

Plenty large enough hole for an ermine attack

I didn't dig it up to see what lies below (that seems rather cruel) but did note the location, and maybe I'll stop by again as the snow melts down to ground level to see what has been created down there.  In the mean time, we'll continue to do our part by fattening up the gray squirrels who live in the high-risk zone above the snow.

On this same walk I found a set of snowshoe hare tracks right on the lake, coming out from a hemlock stand.  This is another prey animal that all the predators still have access to, though I don't see many signs of hares around the Lakes Region.

Snowshoe hare track near the Harris Conservation Area

I also came across a set of fresh porcupine tracks;  following them for a stretch I saw that it had checked out a beech tree but decided that wasn't its cup-of-tea, so it moved on.

Mr. Porky didn't like this tree

It's next stop was a hemlock - always a favorite.

Here he found something to his liking

And there were ample signs that he dined here.

Hemlock debris dropped

Whenever you find this kind of hemlock debris on the snow you know a porcupine has been up there cutting off and chewing (not very carefully) on the tender branches.  He must have eaten his fill, as after this stop he retraced his steps right back along the same path he came in on.

Two sets of tracks, in and out

Finally, on this same trek I came across a recent blowdown with some very interesting markings on the wood inside where it split open.

I was fascinated as well as perplexed as to what could cause these markings deep inside the trunk of a tree, so I sent some pictures off to Shaun Lagueux and Andy Fast, our town and county foresters respectively, for some expert input.  They both immediately responded, saying it is spalting due to a fungus.  I'll have to do some research on this and will report what I learn next week.

Intriguing marks deep inside the trunk of a hemlock tree