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Flood Categories
Minor - Some public inconvenience, but minimal or no property damage likely.
Moderate - Closure of secondary roads. Transfer to higher elevation may be necessary to save property. Some evacuations may be required.
Major - Extensive inundation and property damage. Usually characterized by the evacuation of people and livestock and the closure of primary and secondary roads
Record - The highest observed River stage or discharge at a given site during the period of record keeping.

Categorical Flood Forecast Verification System - Cumulative River Forecast Center Verification Statistics
3rd Quarter (APR 2014 - JUN 2014) FY2014

Average Lead Times Average Lead Time
A categorical lead time is the number of hours from the time of forecast issuance to the time of the forecast hit. A lead time is only computed when, (1) the ordinate's forecast and observation are in the same category, and (2) the previous ordinate's observation was lower than the current category. This restricts lead time calculations to instances where the stage is rising, and crossing categories.
Average Lead Time Trends
Minor Flooding
Average Lead Time of Minor Flooding
Moderate Flooding
Average Lead Time of Moderate Flooding
Average Categorical Errors
This is the amount the forecast would have to be changed to reach the observed category. Categorical error is only computed when you have a miss.
Average Categorical Errors
Long Term Averages
Average Categorical Error - Long Term
Average Lead Time of Minor Flooding
Number of Events
Average Lead Time of Moderate Flooding
Average Lead Times Number Of Events
The number of events during the quarter for each flood category.
False Alarm Ratio (FAR)
The number of missed categorical flood forecasts divided by the total number of categorical flood forecasts issued.
FAR = (False Alarms / (False Alarms + Hits) ) {0.00 is best}
Day 1 Day 2 Day 3
False Alarm Ratio Day 1 False Alarm Ratio Day 2 False Alarm Ratio Day 3
FAR Trends
Minor Flooding
POD of Minor Flooding
Moderate Flooding
POD of Moderate Flooding
Probability of Detection (POD)
The number of categorical flood forecast hits divided by the total number of categorical flood forecasts observed.
POD = (Hits / (Hits + Misses + No Forecast Misses) ) {1.00 is best}
Day 1 Day 2 Day 3
False Alarm Ratio Day 1 False Alarm Ratio Day 2 False Alarm Ratio Day 3
POD Trends
Minor Flooding
POD of Minor Flooding
Moderate Flooding
POD of Moderate Flooding