By Dana and Kay Little, July 2015
Who has seen the wind? / Neither you nor I: / But when the trees bow down their heads. / The wind is passing by. –Christina Rossetti (1830-1894)
The weeping willow outside my window, roots firm in the waterlogged soil, bends and sweeps away from the north wind. A wind from the south brings warmth. Upturned leaves of red maples announce a coming storm. As I dig in my garden, a steady breeze keeps the black flies away. Leaves scuttle across the water and pile up on the beach, giving me mulch for blueberry bushes. A northeast winter wind brings piling snow. We can’t see it but we feel its effects. And living here, there are so many things to learn about the wind.
If you stand on the shore facing into the wind, the water from the pond is pushed towards you and is slightly deeper where you stand. This oscillation in the water level is called a seiche. And in summer, the wind acts primarily on the surface, causing the seiche to push warm water towards you, giving you a deeper layer of warm water. If the wind is at your back however, the seiche will take away warm surface water, making your swim colder than usual. Any time the wind blows it creates turbulence in the water. This creates spirals which rotate in opposite directions. These spirals travel in parallel lines in the direction of the wind and are called Langmuir rotations. Where two spirals meet they are up-welling on one side and down-welling on the other side. Heavy particles collect on the up-welling side; buoyant particles (foam, bits of plants, etc.) on the down-welling side, creating lines on the surface of the water like small streams. The water between the lines may form smoother areas, creating surface patterns that shift with the wind.
At times, we also see foam on beaches. It’s typically a light tan, has an earthy or fishy smell, and dissipates quickly when the wind dies. Decaying plants in the water release natural compounds that function like surfactants in the same manner as soap. Then, when wind agitates the water, we see the formation of large bubbles. Excess phosphates in the water form runoff or soap can also cause foam which will be white, have a perfume type odor and persist after the wind dies. On windy days, the foam I find on my beach has always been composed of natural substances and indicates only that we have a biologically productive pond.
One of the most reliable winds on the pond is the sea breeze that comes off the ocean on warm summer days. Sun heats up land faster than water causing air over the ocean to be cooler than over the land. In summer, all along the coast of Maine, warmer air over land rises, and cool ocean air rushes in to fill the void—a sea breeze, also called an onshore wind. On Taylor Pond, starting about 2:00 PM, this sea breeze blows from Crescent Beach on the south end up to Lapham Brook at the north. On hot summer days a strong sea breeze often appears; then, waters at Crescent Beach can be as smooth as glass for the swimmers, and at the north end you see sailing classes battling foot-high waves. The same day, the same pond, two entirely different experiences.
Zephyr winds form in the same manner as the sea breeze but are formed right on Taylor Pond. Fetch describes the longest distance wind can travel across the water unimpeded by land. Taylor Pond is roughly 4000 by 9400 feet measuring east to west and then north to south. When sailing on Taylor Pond, keep away from shore so that fetch is maximized to increase your speed. Hills and trees obstruct the flow of wind, often cutting sailing speed in half. Winds on the pond can be fickle and shift 90 to 180 degrees at a moment’s notice, dumping unwary sailors into the water. A sailor reads the wind on the water’s surface. Waves on the Pond form perpendicular to the direction of the wind. A set of waves from a new direction mean the wind will change direction even before the waves reach your boat. Ripples on the surface changing to small wavelets, indicate a stronger wind.
In summer, on a sunny day, when the winds blow mostly from the southeast, the cove where I live on the southwest corner of the Pond is protected from the wind. The water may be as smooth as glass here, but a hundred yards out there will be visible ripples in the water. To catch the wind, I have to get my sailboat to those ripples. And farther out, looking at the waves and knowing the Beaufort Scale, I can estimate the speed of the wind. The table below describes part of the Beaufort Scale. When speaking of wind speed over water we usually speak of knots with one knot being equivalent to approximately 1.15 miles per hour.
|BeaufortNumber||Description||Wind Speed (in Knots)||Lake Condition||Land Condition|
|0||Calm||0-0.6||Flat||Smoke rises vertically|
|1||Light Air||0.6-3||Ripples without crests||Smoke moves in wind direction, leaves do not move|
|2||Light Breeze||3-6.4||Small wavelets, crests not breaking||Wind felt on exposed skin, leaves rustle.|
|3||Gentle Breeze||6.4-10.6||Large wavelets, crests begin to break, scattered whitecaps||Leaves and small twigs constantly moving, light flags extended|
|4||Moderate Breeze||10.6-15.5||Small waves with breaking crests, frequent whitecaps||Dust and loose paper raised, small branches begin to move.|
|5||Fresh Breeze||15.5-21||Moderate waves, many white caps, small amounts of spray||Branches of moderate size move, small trees in leaf begin to sway.|
|6||Strong Breeze||21-26.9||Long waves form, white foam crests frequent, airborne spray present||Large branches in motion, whistling heard in overhead wires.|
The scale continues on to 12, which indicates hurricane force winds, over 63 knots. For sailing I am reluctant to go over 5, for canoeing I generally will not leave shore if the number exceeds 2, and for kayaking, 6. For most people, long rolling waves, white caps and spray in the air signal the need to stay on shore and simply enjoy the wind blowing in their face.
Feel it, smell it, taste it, Wait for it, dread it, fight it. Ride it, embrace it, thank it, Who can ignore the wind on Taylor Pond? Neither you nor I.