Peakflow Forecasts Header

PORTNEUF--AT TOPAZ
   State:  Idaho    County:  BANNOCK
   Latitude:  42 37' 30" North    Longitude:  112 5' 16" West
   Elevation:  4918 feet
   Supporting WFO:  Pocatello    
   Action Stage:  3.5'   Flood Stage:  4'

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.

PORTNEUF--AT TOPAZ   (TOPI1)
Forecasts for Water Year
2025
Ensemble Date: 2025-07-18
Forecast Period: July 18 to November 1
Exceedence
Probability
Stage
feet
Discharge
CFS
Probable
Date of Peak
95 % 2.86 165 2025-07-19
90 % 2.87 166 2025-07-24
70 % 2.97 186 2025-09-09
50 % 3.06 208 2025-09-22
30 % 3.18 236 2025-10-04
10 % 3.33 276 2025-10-28
05 % 3.40 298 2025-10-30

Peakflow exceedence plot for TOPI1

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