Be it flakes or drops, specks of dirt start the downfall of rain or snow

Image 1 of / 1 Caption Close Be it flakes or drops, specks of dirt start the downfall of rain or snow 1 / 1 Back to Gallery

Another snowfall? What a dirty trick -- literally. The snowflakes that fell Friday may have looked white and pure, but each carried a dirty little secret from its past. Each one has a very tall tale to tell.

Far up in the sky, water molecules float in the wind. Some evaporated from the mid-Atlantic, others from Italy, or New York City's Central Park, Arctic ice fields, or even Brazilian rainforest canopies. All were wind-stirred together in the atmosphere. Wherever they're from, these water molecules float alone, single, unimaginably tiny and absolutely invisible to our eyes: one lonely H-two-0h.

You can't see this water vapor, but it is there, like the "empty" space just above the spout of a teapot boiling on your stove. Below the steam cloud, there is a strange space of ... nothing.

When the water vapor cools as it hits the air in your kitchen, those invisible molecules get chilled. They slow down and clump together. Once the molecules form minute little balls, like in the cloud of steam over your teapot, their surface tension resists any and all other water molecules. The droplets are too small to see, one ten-thousandth of an inch across. Millions of them together can form a foggy haze - or a cloud on high. They are too light to fall as rain or as snow. So how do big, heavy raindrops form?

Enter, dirt. Air is full of it. Although it looks clear, there are billions of tiny particles floating around in the air between your eyes and this newspaper: salt crystals, dust, soot, particles from smokestacks, car exhaust, forest fires, distant dust storms and more. You can't see these specs of grit, for they are one one-hundredth the size of those invisibly small balls of water.

Every single snowflake or raindrop has a dirt speck inside. Those same water droplets who shunned each other in pure water vapor will shamelessly glom onto any particle of dirt that floats by. Once the glomming, or condensation, begins, other droplets hurry to join. Now the invisible droplets grow to visible size. In the summer and down near the warm Earth, they form as liquid rain. In the winter or high in the sky, they freeze as ice crystals.

Other molecules and droplets gather. Presently the water drop -- or snowflake -- is so heavy it begins to fall under gravity's pull. Down it comes to Earth to coat your driveway yet again under this spring snowstorm.

Last night you set your clocks ahead an hour. It will feel like you have an extra hour of light in the afternoon today. Suddenly it seems the season has lurched ahead with the clocks. It feels spring-like! Will this nor'easter set the season back?

Look at the bright white snow. From where you stand, you can only see the sunlight reflecting back to your eyes. What you can't see is how much light filters through and between those snowflakes to create a dreamy, milky glow under the snow.

Down there, green plants are awakening. Photosynthesis is chugging along in dandelion leaves, today. The plant let all its big leaves die off last fall, but grew a flat little cluster of leaves for the winter. Whenever it has been sunny, this rosette has been making food and stashing it away in its root. That way, when this wintery weather finally stops, the dandelion is ready to explode into growth.

Skunk cabbage is ready, too, poised in the swamps. Onion grass tips are peeking out into the snow-light of spring. Snowdrops and crocus are using every moment of extra snow-filtered sunlight, to build their strength for the moment they'll burst forth. The early dandelion gets the warmth, and a head start on the season's growth.

Don't cuss the white stuff as you shovel it. Give thanks. It is watering all the plants beneath. It is refilling the groundwater reserve reached by your well or city water system. It replenishes the ponds and rivers with molecules from everywhere. That water is the ultimate blessing, making your life -- and all others -- possible.

Enjoy Guilford naturalist and children's book author Kathleen Kudlinski's daily nature notes and thoughts at her Pondside Place blog, www.kathleenkudlinski.com. Email her at Kathkud@aol.com or write to her c/o the Register, 40 Sargent Drive New Haven, 06511.