Ruber keeping cool 50 feet down the flume

"The Flume" is a V-shaped, usually dry, concrete aqueduct 30 miles east of San Diego. It is covered in places where rockslides are likely to block it, and after walking along the top of a covered section and reaching the next open stretch, I heard the unmistakable sound of an annoyed rattlesnake coming from the dark, cool, covered section I had just stomped across. I crouched down to accommodate the 5' ceiling, turned on my flashlight, and shuffled 50 feet into the covered section where I found this 4' long Red Diamondback keeping cool on the ledge where the "roof" meets the sides of the flume.