**Frost**

One morning in the fall we wake to find a white coating on everything: grass, rooftops, plants, cars and anything which got in it's way. "What is it?" we ask. "Frost", someone says. Where did it come from? How did it get here without us hearing it and waking us up?

Frost is a light feathery deposit of ice caused by condensation of water vapor, directly in the crystalline form, on terrestrial objects whose temperatures are below freezing. The process being the same as that by which dew is formed, except dew occurs when the temperatures of the bedewed object is above freezing.

The process whereby water changes from the vapor stage to the solid stage bypassing the liquid stage, is called: "Deposition". The opposite process: When water changes from the solid stage to a vapor stage bypassing the liquid stage, is called: "Sublimation".

Frost is designated as light, heavy, or killing. LIGHT. Signifies one which has no destructive effect to tender plants and vines. HEAVY. A copious deposit but one which does not kill the staple products of the locality. KILLING, sometimes referred to as "Black Frost. One which is destructive to vegetation and staple products, and turns the vegetation black.

My wife Virginia, Gini is a Cooperative Weather Observer. Since 1986, Gini has been observing and recording max and min temperatures and precipitation readings here in Bath. Looking over her records, the earliest day in the fall of the season when the temperature dropped below freezing was 30 degrees on October 4, 1996. The latest springtime reading of below freezing was 28 degrees on April 23, 1989.

© 2003 Charles A. Giannetta