Nature Notes, by Jim Gilbert
If you have the opportunity, take a walk in the woods or in a park, or even around a city block on a December night when the moon is full, or nearly so, and there is a good covering of snow on the ground.
A walk under the full moon is worth the discomfort of the cold, but remember for those who want to be outdoors, usually there is no such thing as bad weather, only bad clothing. Always dress in layers during a Minnesota winter.
Once you are outside, your eyes adjust to the moonlit landscape quickly and you notice the sparkling light on the snow and the wondrous silhouettes of the trees, and those dark tree shadows. Most anyone doing this adventure mini-trek, with or without snowshoes, with our without a companion, hopes to hear the hooting of a great horned owl. But it’s the cold silence and the light from the moon that gets us thinking and restores our minds.
Just thinking about the moon is fun. Probably no other celestial object is held in greater affection than the moon, unless it’s our closest star, the sun, which is the source of the moonlight. The moon is linked to romance in our culture.
During a full moon we see face-like features in the light and dark pattern of its disk.
We watch it go through all of its phases during a month and find beauty in all of them. Both the words “month” and “moon” are derived from the same root, which means “to measure,” and our most important tool for measuring time, the calendar, was designed around the moon’s phases.
The average month of 30 days coincides closely, though not exactly, with the 29 days, 12 hours, and 44 minutes it takes for the moon to make a complete circuit around the Earth. And the period between like phases — from one full moon to the next, for example – is close to 29 1/2 days.
The full moon for this December is tomorrow, but tonight and through New Year’s Eve we can enjoy bright moonlight on clear or partly cloudy evenings.
What’s happening outdoors now?
Lake Waconia has been frozen over since Dec. 10, and Swede Lake near Watertown since Nov. 24. The tree shadows on white snow are spectacular.
December sunlight casts the longest shadows of the year. Fresh snow reflects close to 90 percent of the sun’s radiation from its surface, and the intensity of the sunlight is now just a quarter of the maximum level we had back in June. No wonder we experience cold days!
The sun no longer creeps southward, but each sunset moves a little to the north. As of today, 2 minutes of daylight have been gained since the winter solstice on Dec. 21.
We can take comfort in that. Below zero temperatures, or close to that, bring elegant frost designs to the insides of some clear glass windowpanes. The patterns come in swirls and feathers, fronds and trees.
On Dec. 27 a year ago
The landscape was brown. The day before we had experienced a record high of 52 degrees, but the 27th with temperatures in the 20s and 30s and sunny skies, was a near perfect day for sailing an ice boat on Lake Minnetonka or doing some hard water fishing on one of the many local lakes.