Thursday, December 18, 2014

Geo 730: December 17, Day 716: Diurnal Stream?

The reason for the question mark in the title is that I'm not sure "diurnal stream" is a valid term, nor the correct one for this situation. Basically, snow melt from ice and snow fields above this spot doesn't melt during the night, so the water flow stops. Then, during the day, if it's warm enough, melting starts again, and the stream gets water. So this stream, at this point at least, flows in stop-and-start daily pulses. I'm not sure I've seen anything like this before, but thinking about it, it doesn't seem it would be all that unusual in alpine settings during the right part of the year. This is one of a series of photos I'd intended to post as animated gifs, but this set is too shaky, with too many out of focus or blurry. The second set has too much in shadow, and doesn't really illustrate the advancing water front very well. And the third, well, long time followers may remember I posted that gif nearly two years ago to mark the end of the first week in the Geo 365 series. That post includes a more complete description of how we happened to discover the nature of this stream, and how we found the daily front of the flow. In this photo, the leading edge is just below and to the left of the small cobble near the middle.

Photo unmodified. October 10, 2012. FlashEarth location.

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