River temperatures have climbed to 28°C as streamflow has nearly ceased,…

River temperatures have climbed to 28°C as streamflow has nearly ceased, concentrating heat and dissolved nutrients in waterways already listed as impaired. This is the moment when oxygen levels collapse. Chinook salmon and trout in these tributaries are now well past their thermal stress limits — unable to extract sufficient oxygen from water this warm, their metabolic demands climbing even as the available oxygen falls. The conditions that looked tolerable a few weeks ago have turned acutely hostile.

This convergence of heat, low flow, and pre-existing water-quality impairment creates a lethal window. Recovery depends on rain that breaks the drought and restores stream volume — but that relief cannot come too late.