From Fishbio– Warm weather in winter and early spring, as we’ve experienced during the last several years of drought, can cause the stored snowpack to melt earlier than normal. This leads to lower river flows in the late spring and summer months when temperatures peak and the rivers need the cooler runoff. As described in a previous FISHBIO post (Fish in hot water), fish encounter a variety of problems when water temperatures are too hot, such increased susceptibility to disease and injury, or even dying outright. Chinook salmon are sensitive to temperature, and rely on timely, abundant, and cool water to spawn, rear, and migrate so the amount of water stored as snowpack is extremely important for survival. (more).