Keeper’s Log: Ominous ice

The wall of ice advancing up the river. (photo by Anna Landewe)

The wall of ice advancing up the river. (photo by Anna Landewe)

On Tuesday evening, January 26th, I returned home to find the dock at a precarious angle with large chunks of ice wedged underneath. My wife Anna described what happened: an incoming tide and southerly wind pushed drifting ice from the Hudson River into the mouth of the Esopus Creek. The ice floes halted momentarily, but the tide and wind kept pushing. Large slabs of ice kept creeping closer, overriding each other and piling up to form a wall. Anna climbed the tower to see that the wall of ice extended the width of the river, slowly advancing with the tide.

The lighthouse stood firm against the icy onslaught as the unstoppable force of the ice floes met the immovable stone base of the lighthouse. However, the dock did not fair so well, succumbing to the pressure of the ice. It all happened in a matter of minutes. Lumber cracked. Ropes snapped. Steel pilings buckled. Metal brackets bent. The old dock has been through a lot in recent years. It was damaged in previous floods, and now the ice dealt it another blow.

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Two days later in the dark of night, ice floes piled onto the flats just north of the Lighthouse on an ebb tide. We listened in the dark for what we couldn’t see. The cacophony of the crashing ice was described by a guest as the coarse sound of someone slowly grinding a knife blade on a whet stone. Another guest said it sounded like growling. The moving ice is certainly menacing. It was worrisome to think what sort of havoc it might be wreaking in the dark. Daylight revealed impressive hummocks of ice mounded up in jagged piles on the tidal flats, but thankfully no damage.

Until the river freezes in earnest and the ice holds fast to the shore, it is apt to plow into things while floes continue to drift with the tidal currents. Likewise, during the break up in the spring, the moving ice can leave destruction in its wake. The brute force of the ice floes is like a slowly rolling freight train.

Ice was to blame for the demise of the first lighthouse at this location. Built circa 1835, the building stood on a pier constructed of wooden cribbing with stone fill. Over successive winters, it became a casualty of the river ice. The fingernails of the frozen river tore away at the timbers, undermining the foundation of the lighthouse. An engineer’s report in 1855 noted the pier appeared “to have been injured and shaken by the floating ice.” It was feared that the lighthouse would be carried away by freshets when springtime runoff brought down the ice in a rush.

The need for a new lighthouse on a more substantial foundation became obvious. In 1869, it was replaced by the current lighthouse on a foundation of massive limestone blocks, some of them weighing over four tons. As a fortification against river ice, the circular stone base stands twelve feet high and sixty feet in diameter. Thus protected from the ravages of ice floes, the lighthouse remains to this day.

The lighthouse is safer not only due to its sturdy stone base but also since the danger of destructive ice floes is much less now than in the nineteenth century. Coast Guard ice breakers prevent the formation of large ice jams on the tidal Hudson, and flood control dams near the headwaters in the Adirondacks reduce the size of springtime freshets. Less worry makes the river ice easier to enjoy from an aesthetic perspective as fear fades to appreciation and awe.

While daytime and nighttime temperatures continue to alternate above and blow the freezing point, the river displays ice in many of its forms. To name them is a lesson in wintertime vocabulary. The first phase of freezing is known as frazil, a shean of fine needlelike spikes or plates of ice coating the surface of the water. In a later stage of freezing, the spicules combine to form a soupy layer called sludge. On windy nights, as waves churn the newly forming ice, the shoreline gets coated with an accumulation of spongy white ice lumps known as shuga. On calm nights, a thin layer of skim ice forms on the surface. While the ice sheets remain thin, they remain somewhat elastic, bending and undulating with waves and swells. Once the ice reaches more than a few inches in thickness, it turns rigid and tends to break when jostled, fracturing into elaborate geometric shapes. As the ice repeatedly breaks up and refreezes, the fragments form masses of brash, frozen conglomerations of other forms of ice.

In recent weeks, bald eagles have frequented a nearby tree, perched for hours at a stretch, watching openings in the ice for any sign of prey or carrion. Like them, I could stare at the ice in tireless fascination, not for food but for a feast for the eyes at the continuous parade of frozen forms. It is a temporary topography to survey, a varied array of ridges and hummocks, flaws and fissures. So long as I remain engrossed in the beauty of the wintery landscape, I can enjoy a brief mental break from thinking about dock repairs.

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