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Tackling the Climate Challenge


Welcome to the Lower Snake and Columbia River Hot Water Report, week nine. This weekly report presents the conditions on the Lower Snake and Columbia Rivers via graphs, analyses, and stories. We have been tracking the rivers as they become too hot for migrating salmon, as well as the return of each individual salmon species. Reports will conclude soon, once temperatures settle below 68°.

In 2015, extreme water temperatures killed upwards of 300,000 salmon in the Columbia Basin. Extinction is looming for wild Snake River salmon and steelhead, with myriad threats facing these dwindling stocks. As each salmonid species journeys through the Columbia and Snake, we will highlight its unique attributes and discuss how different species respond to increasing river temperatures. We’ll also hear first-hand from scientists, tribal fishers, guides, and citizens on the Columbia and Snake rivers throughout the summer.


Will you be on the river this summer? Do you have a story or photo you would like to share?  Please send them to Jacob Schmidt

If, in the course of your river trips this summer, you come across a dead sturgeon, remember to contact the Washington Department of Fish and Wildlife.

The Hot Water Report is a joint project of the Save Our wild Salmon Coalition, Idaho Conservation League, Columbia Riverkeeper, Idaho Rivers United, Friends of the Clearwater, and Washington Sierra Club.

Check out previous Hot Water Reports here.



The daily mean temperature at the forebay (upstream reservoir) of each dam is represented in the solid lines, while the 10 year average (2008-2017) for each reservoir is represented by the dashed line of the same color. The dotted line across the top of the graph represents the 68° survival threshold for juvenile salmon. The longer temperatures remain above 68° and the farther the temperatures rise above 68°, the more severe the effects, including: increased metabolism, increased susceptibility to disease, reduced fecundity (reproductive potential), and/or death.

If you are unfamiliar with the location of the Lower Snake and Lower Columbia dams, you can find them on this map.

Temperatures at all four of the Lower Snake dams have began to decrease over the last three or four days. Daily highs are still breaking above the 68 degree survival threshold, with the exception of Lower Granite and Little Goose, whose high temperatures measured 67.6° and 67.5° respectively on August 30th. Continuing along last week’s trend, air temperatures have been cooler overall this week. Nonetheless, warm temperatures in the 80’s and occasionally the low 90’s persist. Temperatures at Ice Harbor, the furthest downstream of the lower four Snake River dams, remain the warmest and continue to register well above the 68° survival threshold. Meanwhile, at the forebay of Lower Granite dam - the furthest upstream and most direct recipient of high elevation streamflows - temperatures have begun to dip back below the 68° threshold.

The general trend toward lower temperatures apparent on the lower Snake is also evident on the lower Columbia. Though the temperatures at the forebays of all four dams have begun to dip, they remain above 68°. McNary is the first of the four dams to see days without a daily max temperature above the threshold. Yet, until all daily temperatures remain consistently below 68°, fishing closures will likely continue. Last week’s night fishing closure remains in place, as does the closure at the mouth of the Deschutes.



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Temperature data included in these reports come from the USGS Current Conditions for Washington State and the Fish Passage Center. Graphs and tables were assembled by SOS Staff.

2018 Columbia-Snake Basin Adult Salmon Returns – year-to-date

Fall Chinook

Chinook arriving at the mouth of the Columbia after August 18 are no longer counted as Summer Chinook, but rather as Fall Chinook. Snake River Fall Chinook have fared far better than Spring/Summer runs, but are still listed as a threatened species. There was talk of delisting the species after the banner year of 2014, in which more than 50,000 chinook returned to the Snake River and its tributaries.


So far, this year’s fall return has been far below average. However, the improvement over 2017 results at this point in the year gives hope that we might see a return to the sort of recovery that was underway in the first half of the decade. These returns are, however in a very early stage. The numbers on the graph above represent less than 30% of the complete run.


New Links

Lower Granite Water Remains Cool; Snake River Sockeye Run Nearly Complete At 272 Fish

Columbia Basin Partnership Develops Preliminary Abundance Goals For Salmon, Steelhead

Biologist Explains Why Last Year’s Idaho Wild Steelhead B-Run Better Than Dam Counts Showed


Past Links


IFiber One: Entire State Drying Out Under Drought Like Conditions

Oregon Whitewater: Snake River at Hells Canyon

Spokesman: Salmon, steelhead fisheries on Columbia restricted


Lonesome Larry

Times of London: Scottish Heatwave is Disastrous for Salmon Industry

WSU: Demand factored into Columbia River Basin’s future

Columbia Basin Bulletin: With Run Downgrade, Summer Chinook Fishing Below Bonneville Dam Ends Early; Sockeye Above Forecast  

Columbia Basin Bulletin: Corps Second Spill Report to Court Details Impacts of High Flows

Hatch Magazine: Trout and Water Temperature: How Hot is Too Hot?

Alan Lierres Fish Hunting Report, July 4

Oregon Live: Columbia River spring chinook salmon run prediction downgraded OSING TO ALL FISHING

Oregon Live: Oregon closes steelhead sanctuary off mouth of Deschutes to all fishing

CBB: State Of The Climate Report: 2017 Was Third Warmest Year On Record

CBB: River Managers Opt To Save Cool Dworshak Water For Upcoming Salmon/Steelhead Migration  

Spokesman: With climate change warming Washington’s waters fish are left seeking a place to chill

Heat Wave: Renewables pass a test, but greater challenges await

First Sockeye Arrives at Redfish

Alan Lieres Fish Hunting Report for August

Rule Change for Columbia River Anglers

TCH: Fishing halted in Tri-City area due to hot river waters

CBB: Tripped Generators At Dworshak Temporarily Interrupts Water Releases Cooling Clearwater, Lower Snake  

Eastern Oregonian: Pacific lamprey swarm Umatilla River in best numbers in years

Oregonian: Tribes return to the chilly waters of Willamette Falls for annual lamprey harvest

Portland Tribune: Mitigating the migration

Nez Perce Tribe Lamprey Restoration Project

DART Columbia Basin "Quick Look" Adult Passage

CBB: River Managers Ponder Passage Gaps For Snake River Sockeye At Lower Snake Dams  

Columbia Basin Bulletin: Climate Forecast Favors Onset Of El Nino, Could Mean Warmer Winter In Northwest

Drought Conditions Hitting Oregon, Washington; Most Streamflows In Basin Remain Healthy

CBB: With Temps Rising, Corps Cools Snake River With Dworshak Water To Aid Endangered Snake River Sockeye

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