City Creek Nature Notes – Salt Lake City

December 14, 2016

December 14th

Filed under: picnic site 3, Stream — canopus56 @ 6:55 pm

The Golden Ribbon

4:00 p.m., December 14th, 2016. Today, it is overcast with a light rain during the afternoon. At sunset, as I drive out of the canyon, the sunset behind the clouds makes the deepest of pink colors.

4:00 p.m., December 11th. Up and down canyon of picnic site 4 is a short stretch of straight stream, and on the far bank side the ground gently slopes upwards. When the setting Sun leaves the stream in shadow but the farside is still bathed in yellow light, the stream’s surface perfectly reflects the opposite bank. The stream then glows like a dusky ribbon made of gold. The stream is cold but looks like hot lava outpouring from some volcano. The effect only lasts for one or two minutes each evening, and one must be correctly positioned in order to see its brief appearance.

I have seen this effect just a few times since the start of Fall. The rareness of the experience is a matter of computation and probability. What are the chances that I will be jogging past the proper point on the road when the Sun is at a particular angle for a three or four minute period, given that I start jogging at random times between noon and six in the evening? Physics also reduces this to an optical effect of Snell’s ratio, another simple mathematical relationship. At a certain viewing angle, the angle of water’s refraction equals the angle at which light travels from the opposite direction. If the angle is higher, one sees through the water’s surface; if lower, the water’s surface appears black; and, if the angle is equal to Snell’s ratio for water, then the surface becomes a mirror. But this evening, there is more in the glowing surface of this stream than can be expressed by mathematical abstractions of the thing itself. It buoys the spirit against cold.

On December 14, 1914, City Engineer S.Q. Cannon reported that during a harsh winter, teams of men were employed to keep the canals from Parleys Canyon and City Creek that supplied water to the City open and free of ice and snow (Salt Lake Telegram).

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