The cold weather gives rise to ice occurring naturally, with no help from us. The laws of nature precisely govern this phenomenon which causes water in its liquid state to be transformed to a frozen state. Low temperatures chill the water lying on the surface of any collection of water – whether it be a pond or lake, creek or river; and this causes it to sink to the bottom where it becomes dense or heavy. This cold water at the bottom now displaces the warmer water which rises to the top. This process occurs until all the water reaches 39 degrees Fahrenheit at which time the water ceases to sink. The water then continues to cool at the surface and expands until about 32 degrees Fahrenheit and becomes hard. Varying kinds of ice have distinguishing characteristics that are peculiar to each.
This ice first forms on the water’s surface. It is hard and clear and is also referred to as “black ice” because it appear black as you look through it to the underlying water or surface. If covered with enough snow, the “black ice” can be pushed down during cold weather to a depth which causes it to crack and allow water to escape through, creating slush. “Black ice” or dark ice is not safe ice because of its recent formation.
This occurs when slush, melting snow, or water on the top of black ice refreezes. The white, milky, or opaque appearance results from trapped air bubbles within the ice causing a weakening condition of the ice mass. Dark areas in the ice may indicate that water melted underneath the ice surface, thereby thinning the ice. This ice is not safe.
When water is heavier than ice, a warm spell can cause ice to soften allowing the overlapping water to seep down into the ice structure creating honeycomb ice. This also is not safe. Because varing kinds of vegetation rising through the ice absorb heat from the surrounding air and from the sun, the adjoining ice becomes weekened and unsafe.
Gray or Blue-ish Ice
This is the safest ice. Two inches of this will support an average weight person without any difficulty.
One of the safest ways for traveling across ice is to carry an ice probe to determine its thickness. Safe hard ice when chipped with an ice probe will stay in tact and produce a solid “thud” sound. Unsafe, soft ice, by comparison, will chip or break and give off a muted sound. So too, you don’t hear anything when walking on good ice, but walking on thin ice produces a hollow sound.
To play it safe, irregardless of what the ice appears to be, stay off the ice!