Water is the creator of life and destroyer of rock

“Something there is that doesn’t love a wall,” Robert Frost wrote, “That sends the frozen ground swell under it,/And spills the upper boulders in the sun,/ And makes gaps even two can pass abreast.”

Of course — Robert Frost being Robert Frost — the astute reader soon realizes that the “something” to which he is alluding is a symbolic force beyond the natural one of a frost heave. “Frost is writing about something other than FROST,” a professor of mine once told our class, a statement fraught with multiple meanings. 

Nevertheless, this time of year the natural — and frequently destructive — effects of the past winter’s ice are in evidence just about anywhere one cares to look — perhaps most annoyingly in our pock-mocked city streets and country roads.

Appearing first as fine lines often resembling the strands in a spider’s web, fractures caused by the natural wear and tear of moving traffic begin to lengthen and interconnect, producing jagged pieces of gravel and leaving behind little indentations; these then also interconnect and become even larger pits which fill with water — and then the tire of your car hits what looked like a shallow puddle in the road followed by a sickening thud and the shuddering of both car and occupants.

And the culprit is frozen water — or, rather, the alternate freezing and thawing of water, phenomena that occur throughout the winter at our latitudes but become particularly frequent and destructive when winter begins to loosen its grip. 

The phase change of water from liquid to solid and back again wreaks destruction on any exposed porous surface and occurs repeatedly throughout the seasonal transition.

“Stay where you are until our backs are turned!” is what Robert Frost calls the “spell” to keep boulders in a stone wall in place, though the words themselves betray their futility. How often in February do we see work crews filling in potholes with steaming blacktop — only to have the fill ripped out and scattered forlornly over the road surface following the next snowfall or slush storm?

When torrential floods or massive snowstorms occur, we become all too aware of water’s destructive power in its various states, but because of its ubiquitous nature, we otherwise tend to take it for granted.  However, among many other ancient people, the Egyptians knew that their civilization depended upon the water in their great river — Egypt being “the gift of the Nile” — and they worshipped a god called Hapi as its spiritual embodiment; ancient Greeks built temples over springs, whose waters were considered not only essential for life but sacred.

Water is weird

But outside of a science classroom, we often tend to forget just what weird stuff water is. Reversing the behavior of other natural substances, water occupies greater volume as a solid than as a liquid, which is why a can of soda or a bottle of beer placed in a freezer will shatter when the liquid expands as it freezes;  likewise, unlike other substances, its density decreases when it becomes a solid.

And the phase changes of water involve amazing numbers of calories. Physics students know that, while it takes only one calorie of heat to raise one gram of liquid water by one degree Celsius, it takes 540 calories to vaporize that one gram when it reaches 100 degrees Celsius.

Take one calorie out of a gram and its temperature will drop by one degree — but if that gram of water is at zero Celsius, 80 calories must be removed to make it freeze. As it does, it will expand and become less dense, which is why ice floats.

And a good thing it does — for if ice were denser than water it would sink, causing many of our ponds and lakes to freeze solid in winter, wiping out all the life within them.

Most vitally, water is the absolutely essential ingredient for the existence of life as we know it, which is why the scientists known as “exo-biologists” are excited by the prospect of subsurface oceans on the moons known as Europa and Enceladus that orbit Jupiter and Saturn respectively.

Several years back, an early-season hiker on the Indian Ladder Trail at Thacher State Park was injured by a falling cobble-sized rock ripped from the cliff by winter’s ice, resulting in an extended closure of the trail. Apparently trying to conjure images of a dark conspiracy, an area daily newspaper subsequently published a story with a headline to the effect that the park maintenance staff “knew of” the danger beforehand. 

Of course they did — and so did every kid in New York State taking Earth Science! The implication that “something should have been done” is ludicrous. The mile-long trail follows the base of a cliff made of several different rock types, all of which are heavily fractured through natural weathering processes and all of which absorb water that freezes in winter, resulting in the shattering of rock known as “frost wedging.”

A photo taken in the Adirondacks shows a multi-ton boulder of the metamorphic rock known as schist that has been cleaved by this process. No amount of vigilance before the Indian Ladder Trail opened for the season could have accounted for every single crevice or fracture that was in danger of releasing a rock fragment.

The Helderberg escarpment has been eroding for millions of years, and the process will continue for millennia to come.  The broad talus slope that descends from the escarpment into the valley below is made up of billions of tons of rock weathered from it, ranging in size from giant boulders to sand grains — and these fragments do not fall without violent results.

The rocks of the Helderbegs generally fall into one of three types of sedimentary rock, formed hundreds of millions of years ago in the seas of the Devonian Period: limestone, shale, and sandstone.

Of the three, because of its density, limestone is generally the most resistant to weathering by frost wedging, though natural acids in rain and groundwater will cause it to dissolve. From a limestone outcrop south of the village of New Salem, great slabs of rock have been wedged by ice accumulating in the natural fractures in bedrock known as “joint partings,” forming a steep cliff .

Shale is petrified clay and can easily absorb water that can cause a solid rock exposure like one on the Beaver Dam Road above Thacher Park to be reduced to a pile of gravel by frost wedging. The talus slope below the the Helderberg escarpment is formed mostly from the on-site weathering of porous shale and sandstone bedrock, though it is littered with immense jagged boulders of the Manlius and Coeymans limestone layers that have broken away from the cliffs and gone crashing down from the plateau.

Ice Age changes

Much of New York State’s landscape was changed radically starting 1.5 million years ago with the onset of the Pleistocene Epoch, more commonly known as “the Ice Age,” though it was only the most recent of several that Earth has experienced over the billions of years of its existence.

In the Helderberg area, the steep faces and flat tops of Bennett Hill in Clarksville and Vroman’s Nose in Middleburgh show the effects of the movement of the continental ice sheet. Laden with rock fragments torn from bedrock by frost action, the glaciers acted like gigantic bulldozers sculpting and scraping the bedrock, often with spectacular results.

Pyramidal Potash Mountain that looms above Lake Luzerne got its unique shape when several small glaciers descending from its summit tore away its dense metamorphic bedrock.  Had the glaciers persisted for a few more thousands of years, Potash Mountain might have become a miniature version of Switzerland’s Matterhorn.

A graph of daily temperatures as the year in the Northeast progresses from January to June would show a constant variation from cold to warm and back to cold again. It must be remembered that an “average” temperature is simply the mean between two extremes, and it is not unusual in this part of the country to have a day in the 70s in February and a snowy day in May — though the general temperature trend obviously is upward.  

Warm days and below-freezing nights are said to be ideal for maple syruping. But they certainly can wreak hell on our roads and rocks.