Peakflow Forecasts Header

SANDY--SANDY
   State:  Oregon    County:  CLACKAMAS
   Latitude:  45 26' 57" North    Longitude:  122 14' 37" West
   Elevation:  240 feet
   Supporting WFO:  Portland    
   Action Stage:  18'   Flood Stage:  19.3'   Moderate Flood Stage:  20.5'
   Major Flood Stage:  21.5'

Forecasts are calculated from a forecast time series that approximates flow at a 6 hour time step interval. Observed instantaneous peaks can be higher than model forecast peaks.

SANDY--SANDY   (SNDO3)
Forecasts for Water Year 2026
Ensemble Date: 2026-09-15
 Forecast Period: September 15 to January 1
Exceedence
Probability 		Stage
feet 		Discharge
CFS 		Probable
Date of Peak
95 % 10.83 3998 2026-10-31
90 % 11.36 5166 2026-11-03
70 % 14.23 13822 2026-11-24
50 % 15.92 20785 2026-12-05
30 % 16.53 23746 2026-12-18
10 % 19.18 39506 2026-12-29
05 % 20.05 45760 2026-12-31

Peakflow exceedence plot for SNDO3

 Click to download runoff traces used in forecast.  Click for comma delimited data used in plot.csv icon