Particle.news
Download on the App Store
4 ARTICLES
·
4h ago

River Heat Waves Are Surging Across the U.S., Rising Up to Four Times Faster Than Air Extremes

A Penn State-led PNAS study using deep-learning reconstructions links the trend primarily to human-driven warming with regional amplification from dams.

Image
A bull trout.
While air-based heatwaves are obvious, the hidden heatwaves in our rivers have now been uncovered thanks to a new Penn State study

Overview

  • Analyzing 1,471 USGS stream sites from 1980 to 2022, researchers found sharp increases in the frequency, intensity and duration of riverine heat waves.
  • Rivers now see an average of about 11.6 additional days each year above 15°C (59°F), a stress threshold for many species including salmon and trout.
  • The fastest increases occurred in the Northeast, Rockies and Appalachians, while the Midwest showed the slowest rise in warm-water days.
  • Days exceeding 20°C (68°F) rose most in the Southern and Appalachian regions, heightening risks of low oxygen, fish kills, water-treatment costs and energy disruptions.
  • The study defines river heat waves as at least five consecutive days of abnormally high water temperatures and points to operational reservoir releases, riparian shading and improved monitoring as near-term responses.