Wednesday May 20, 2026
USGS —
The study, conducted in cooperation with the Karuk Tribe, the Yurok Tribe and two universities, is the first published documentation of a rain-on-wildfire event directly linked to lethal water-quality conditions in a large river.
The research highlights how continuous water-quality monitoring, uncommon in fire-prone areas, is critical for detecting sudden changes. Using high-frequency monitoring data, scientists revealed how the initial flood wave of stormwater moved quickly downstream while a concentrated pulse of fire-scar material, including ash, charcoal, and sediment left behind by burned hillslopes, arrived later. This caused dissolved oxygen in the water to drop to zero for more than five hours, creating a condition called anoxia, a total loss of oxygen that can quickly kill fish.
“This research provides resource managers and emergency responders with critical information about how post-fire landscapes can affect water quality in ways we haven’t fully understood before,” said Jennifer Curtis, USGS research geologist and lead author of the study. “Understanding these oxygen depletion events helps managers better anticipate and potentially mitigate similar impacts as wildfires become more frequent and intense across the West.”