Glacial melt? Where are you Jimmy? You don't sound like you're from Cooper Country. Out here we talk about snow pack, and how it affects river flow. Glacial melt is something that happens very high up, especially on Mts. Rainier, Adams, Jeff, and Hood. It's a phenomenon for tourists to take pictures of, really.
Regardless, lots of dams control the flow. The Columbia has big ones, and the little rivers have smaller ones, such as the Merwin Dam on the Lewis, or my own Alder Dam system on the Nisqually. The lakes behind them make for great swimming.
But stream flow varies, for sure, and the Columbia has many highs and lows, which we have talked about intensely here. Welcome to the discussion, btw.
Lastly, "glacial melt" and the "retreat" of the glaciers on these mountains is perhaps the most obvious sign of global climate change. The loss of the Nisqually glacier on Mount Rainier is quite dramatic from its position in 1853 at first discovery by white folks to where it is now. The retreat is not only at least 5,000 feet back up the mountain, but the disappearance of ice-mass from the glacial valley is stunning. The dry-but-scarred slopes of the Nisqually basin extend several hundred feet up the sides of the ravine. That's a huge loss of ice, which is now in the ocean and contributing to sea-level rise. Along those lines, one of the reasons I moved to Cooper Country from New York was that the water in NY Harbor was already a foot higher when I left in 1990 than when I was first measured in 1860 by the Union Navy as they were building fortifications to protect the dockyards and ships from Confederate attacks. Further, in my 69 years I have seen dramatic increases in water levels and tide impacts upon NY area sea walls and jetties. High tides now come close to breaching the jetty rocks that were installed when I was a kid. That phenomenon is now ubiquitous, and the phrase "King Tide" is now part of our lexicon to describe the regular, prolonged low-land flooding from tide cycles and not storms.
