As we move into the full swing of summer, water managers are paying close attention to the remaining snowpack in the Sierra Nevada. Each year, water from melting snow flows into rivers, creating important environmental cues for native freshwater species and filling reservoirs, just as agricultural water demands peak during the growing season. But as California gets hotter with global climate change, our snowpack is shrinking and melting earlier in the year (Stewart et al. 2009), profoundly changing snow-dependent river ecosystems (Leathers et al. 2024), and leaving us with less water when people need it most. … Two recent papers from the Berkeley Freshwater group investigated how flow regimes – the natural seasonal patterns of flowing water – are shifting in the state’s rivers.