Inseason Forecasts Snake and Columbia Rivers
Inseason Forecasts use "real time" information about the current status of various Columbia Basin juvenile and adult salmon runs along with current hydrographic information to predict the future progress of the migrating fish.
Smolt Passage
Arrival distributions, historical timing, transport, and survival
for various Snake River yearling chinook, steelhead, subyearling chinook and
sockeye stocks. Forecasts are based on PIT Tag detections at Lower Granite
Dam.
Current Predictions: 2026-04-25
Arrival distributions and historical timing for combined stocks
of yearling chinook, steelhead, subyearling chinook, sockeye, and coho. Forecasts are based on Passage Index
data at each dam, individually. Historically, forecast locations included John Day and Rock Island dams. Please see Chelan Passage Counts forecasts for current Rock Island Dam forecasts.
Current Predictions: 2026-04-25
Arrival distributions and historical timing for yearling chinook, steelhead,
subyearling chinook, sockeye, and coho (Rock Island Dam only). Forecasts are based on Chelan PUD passage counts
at Rocky Reach and Rock Island dams.
Current Predictions: 2026-04-24
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Arrival distributions, historical timing, and survival for specific Snake
River and Upper Columbia River ESU stocks. Forecasts are based on selected PIT Tag detections at McNary
Dam.
Current Predictions: 2026-04-25
Adult Passage
Arrival distributions and total run size for spring and fall adult chinook at Bonneville Dam.
Arrival distributions are forecasted to upstream dams for four stocks: Snake River, Upper Columbia
River, Lower Columbia River, and Hanford Reach/Yakima. Forecasts are based on visual adult passage
counts at Bonneville
Dam.
Current Predictions: 2026-04-25
Seasonal Predictions Shiny apps
Historical and out-of-sample predictions of seasonal survival estimates. Updated annually, post-season.
Smolt-to-Adult Return Survival and T:B Ratio
PIT-tagged Snake River Chinook Salmon and Steelhead smolt-to-adult (SAR) survival patterns across outmigration years and through the outmigration season. Generalized linear mixed effects model with covariates day-of-year (DOY) or river temperature (TEMP) at time of smolt passage at Lower Granite Dam (LGR). SAR survival predicted for smolts from LGR outmigrating to the ocean and with adult returns to LGR. Includes transported and bypassed (T:B) survival ratio.