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Impact-Based Weather Forecasting

Moving From "What the Weather Will Be" to "What It Will Do"

Traditional forecasts tell us how many inches of rain will fall. Impact-based forecasts tell us if roads will flood or trees will fall.

The Two Sides of Impact Forecasting

Understanding Hazard vs. Vulnerability

Impact is calculated by looking at how a physical weather hazard interacts with a specific human environment.

• The Hazard: The physical weather event itself (e.g., 60 mph wind gusts).
• The Vulnerability: Who or what is in the way (e.g., above-ground power lines, old trees, mobile homes).
• The Result: Widespread power outages and blocked roads rather than just a "windy day" warning.

Real-World Impact Examples

How Identical Weather Causes Different Impacts

1. Heavy Rain Impact: Flash flooding in urban areas vs. soil absorption in open farmlands.
2. Extreme Heat Impact: High strain on city power grids vs. crop heat stress in rural communities.
3. High Wind Impact: Structural roof damage, overturned high-profile trucks, and flight cancellations.

Impact Modeling & Preparedness Video

How Emergency Services Prepare

Watch this video detailing how impact-based warnings help cities deploy emergency services before a storm hits:

Project Resources

Click below to explore global impact weather warnings