Authors: Burrell Montz*, East Carolina University, Rachel Hogan Carr, Nurture Nature Center, Kathryn Semmens, Nurture Nature Center
Topics: Water Resources and Hydrology, Hazards, Risks, and Disasters, Hazards and Vulnerability
Keywords: Hydrology, Ensemble Forecasts, Risk perception
Session Type: Guided Poster
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Communicating forecasts effectively requires understanding how intended audiences interpret and use forecast information whether presented deterministically or probabilistically. Prior research has studied how public and professional audiences use and understand probabilistic hydrologic forecast information, but questions remain concerning how uncertainty should be presented most effectively and how to simultaneously present deterministic and probabilistic forecasts without diminishing the value of either. This study investigates these questions in four communities in three regions. Specifically, the Advanced Hydrologic Prediction System and regional hydrographs as well as outputs from the Hydrologic Ensemble Forecast System (HEFS) have been presented to residential and professional audiences in three River Forecast Center service areas (Middle Atlantic, Colorado Basin, and California Nevada). Using scenario-based focus groups and surveys, a first round was undertaken in Owego, NY, Durango and Gunnison, CO, and Eureka, CA using NWS products to assess how deterministic and probabilistic forecasts can best be understood to convey the complexity of certainty and uncertainty in short, medium-term and seasonal hydrologic forecasts. The results of the first round were used to revise the products which were then tested with different audiences in the four communities. Although the National Weather Service is hoping to develop “one-size fits all” products, difficulties arise because of different perceptions and needs in different regions. This analysis addresses 1) differences between resident users and professionals and 2) geographic differences in perceived utility of the HEFS and of the impact that a variation between a deterministic and a probabilistic forecast has on trust in either.