Event Footprint Catalog

What is the Event Footprint Catalog?

The EFC documents the impact of significant weather events by mapping where hazards occurred and how they affected the landscape, allowing users to interpret storm events with confidence. The EFC uses field observations and remote sensing data to generate high-resolution footprints that capture the physical extent of storms and other extreme weather events. The EFC also provides associated metadata and event narratives.

The EFC provides precise, high-resolution information on past storm impacts to help leaders across all industries make informed decisions, manage risk, and enhance operational and community resilience. Users can explore footprints through an interactive map display, tailor results by storm type or severity, download the exact data needed for analysis, and review anomalous seasonal patterns. The data provides clarity on the breadth, depth, spatial extent and impact of each event, supporting users in understanding, preparing for, and adapting to the effects of extreme weather events.

Visit the Our Impact page to discover how climate data helps lower costs, increase profitability, and build weather resilience for businesses and the communities they serve.

What weather events are included in the Event Footprint Catalog?

For this initial release, the EFC includes severe storms (hail and tornadoes). Future updates may expand the tool to include tropical cyclones (hurricanes), winter storms, and other severe weather events.

To provide feedback on the EFC product that improves NOAA’s mission to deliver and disseminate information nationwide, please complete the product survey by opening the EFC application and selecting the “Help improve this product” button at the bottom right of the screen.

Severe Storms

Severe storms are hazardous weather episodes such as tornadoes and large hail that often develop rapidly. They can produce intense impacts over short periods of time. In EFC, severe storm footprints map the areas affected by tornado paths and hail swaths (with estimated sizes of 0.5 inches or greater). These footprints only reflect the areas where these hazards occurred; broader storm systems (such as those producing only rain or lightning) are not represented.

What is an Event Footprint?

An event footprint is a precise, map-based representation of the areas directly affected by a significant weather event. Using satellite and observational weather data, the EFC creates two-dimensional shapes that outline the geographic area impacted by a storm. Each shape contains specific latitude and longitude coordinates and is shaded to reflect the intensity of the event, allowing users to visually interpret storm severity and extent.

The EFC generates footprints by converting authoritative event datasets into map-ready shapes that can be displayed and downloaded. For example:

Tornadoes: Footprints are based on official damage assessment records. Line-based source data is converted into polygons to represent the area of impact consistently.
Hail: Footprints are produced from gridded hail estimates, creating polygons that depict the swath of reported hail.

All event footprints are compatible with common mapping tools. The EFC is updated regularly, but timing depends on source data availability. Hail footprints appear quickly from radar data, while tornado footprints may take longer due to reporting and quality control. The application will include explanations when events or variables aren’t available.

Detailed information about how each dataset is processed is available in the Data Information Sheet.

How do I access the Event Footprint Catalog data?

Interactive Map

Access storm footprint data quickly and visually

Explore hail and tornado event footprints through an interactive map interface. The platform delivers detailed storm impact data within days of an event, allowing users to access critical information quickly and efficiently.

Access Event Footprint Catalog

Bulk Data Download

Download the data you need when you need it

Access event footprints, narratives, and associated metadata through flexible download options. Retrieve individual event data or bulk datasets, enabling efficient analysis and integration into existing workflows.

Download Bulk Data

Seamless Integration

Working with the tools you already use

Footprints from the EFC integrate seamlessly with existing GIS platforms and analytics environments, including applications built on Kinetic Global and ESRI-ArcGIS, supporting easy incorporation into operational systems and analytical workflows.

This text is white.

What information is included for each event?

Each event record provides a comprehensive view of the storm, combining spatial data with descriptive information:

Geospatial footprint data: precise polygons showing the areas affected
Event metadata: location, time (standardized to a consistent reference), and key event characteristics (such as duration, path length, and intensity)
Hazard details: event type and intensity or severity (using hazard-specific scales such as hail size and the Enhanced Fujita Scale)
Event narratives: descriptions of impacts and context (when available)

This combination of information allows users to understand both the geographic extent and significance of each storm event. Footprints include essential information to help interpret the map, such as where the event occurred, when it happened, what type of hazard it was, and how strong it was according to standardized intensity categories.

What are the spatial, temporal, and resolution characteristics of EFC data?

The EFC provides high-resolution, geospatially and temporally consistent footprint data designed for detailed mapping and analysis. All event footprints align to a consistent spatial and temporal framework to support comparison across events and long-term analysis.

Spatial coverage: The EFC currently includes coverage for all 50 U.S. states and select U.S. territories, depending on event type and observational data availability. Coverage may vary by hazard due to differences in radar and sensing infrastructure. Additional regions and event types may be added in future releases. When data is unavailable for a selected event type, region, or date range, it is typically because no source data exists for that selection or it falls outside the coverage or update latency. In these cases, the application displays the message: “There are no records available to display.”

Temporal coverage: The EFC includes historical events based on the coverage of underlying NOAA data products and is updated as new weather data becomes available.

Tornadoes January 2010 - Current
Hail October 2020 - Current

Update frequency: The EFC updates automatically every 24 hours as new weather data becomes available, but the timing of updates depends on source data availability. Hail footprints typically appear quickly from radar-based datasets, while tornado footprints may take longer due to reporting, verification, and quality-control processes.

Spatial resolution: Resolution varies by hazard type and source dataset:

Tornado footprints are derived from ground-based damage survey data and represent mapped damage paths based on official assessments.
Hail footprints are generated from radar-derived gridded data at approximately ~1 km spatial resolution.

Detailed information on underlying datasets, processing methods, and data characteristics is available in the Data Information Sheet.

How do I use the Event Footprint Catalog to find storm impacts and narratives?

Filter events by date range, location, event type, hail size, or tornado intensity to find the most relevant results. Choose an event category and define a custom date range to explore historical events in a specific area or timeframe. Use the map tools—zoom, pan, or draw—to refine searches, or use the event table to search by event name or apply filters.

The EFC provides detailed metadata for each footprint that describes the event, including information such as the start and end time and the location of a tornado path, along an event narrative. These narratives describe the unique human, environmental, and structural impacts that explain what happened, and why it mattered. The narratives originate from the underlying source datasets (for more information, see the EFC Data Information Sheet) and are not generated by the EFC.

Each event is available in GeoJSON and CSV files that can be seamlessly integrated into GIS platforms and analytical workflows.

Watch the EFC demo video to learn more about key workflows and how to explore and filter events! [Placeholder for EFC demo video]

Example views of the Event Footprint Catalog interface

This snapshot of the EFC interface shows severe weather event footprints near Troy, Alabama, on March 16, 2025. Color-coded footprints represent different event types and intensities, including tornado paths and hail swaths. The sidebar lists each event footprint displayed on the map, including the event type, start date, and intensity. Users can interact with the map to explore impacts, select individual events for more details and narratives, and refine results using filters.

Snapshot of the EFC interface shows color-coded paths for tornadoes (EF1–EF3 in red), and hail swaths (0.1–2+ inch in blue). A sidebar lists each event footprint with its type, start date, and intensity, corresponding to the features shown on the map.

Clicking a footprint in the sidebar opens a pop-up with event details, including type, start and end times, start and end locations (town, county, latitude/longitude), magnitude, and a full narrative describing the event. This provides both spatial and contextual information about severe storm impacts.

A weather map showing tornado and hail footprints. An information box on the left-hand side details a hail event, including size, date, and event narrative showing paths of severe storm events, with colored areas indicating hail and tornado strengths. There are event details shown in a sidebar; selecting one brings up a second sidebar showing detailed information described in the text section.

Severe Storms Data Sources

DAT footprints are constructed from complete geospatial data from storm surveys conducted by NWS personnel. Storm Events Database (SED) includes information from the DAT, events that predate the DAT, as well as footprints that are reconstructed from start and end locations.

Tornado

Hail

Multi-Radar/Multi-Sensor System

Questions about the data sources? Contact:

Damage Assessment Toolkit: nws.dat.support@noaa.gov
Storm Events Database: ncei.orders@noaa.gov
Multi-Radar/Multi-Sensor System: idp-support@noaa.gov

Version History

Version 1.0 (Launch date 2026)

Online access to the Events Footprint Catalog was first provided in 2026. This initial release is focused on delivering downloadable event footprints for the severe storm events category, consisting of tornado and hail data.

How does the Event Footprint Catalog support decision-making?

Organizations and businesses need reliable climate and weather information to manage risk, plan operations, and make informed decisions for both long-term strategy and day-to-day operations. The EFC translates detailed historical storm observations into clear, map-based insights that help organizations understand where extreme weather has occurred and how it may affect assets, infrastructure, and operations. These precise records of past events make it easier to anticipate future risk, identify vulnerable areas, and make more informed planning and investment decisions.

NOAA worked with multiple industry sectors to co-develop the EFC. These partners work with NOAA to make its data, products, and services more helpful for real-world decision-making. NOAA is committed to helping businesses and communities assess risk and become more resilient to future weather and climate extremes. Learn more about these partnerships and their impact on the Our Impact page.

Explore how different industries apply EFC insights to support planning, reduce risk, and strengthen resilience:

Businesses and Communities

Explore where severe weather has occurred to better understand local risk and past impacts.
View storm footprint maps to see how specific areas were affected, not just where storms were reported.
Use historical event data to inform personal, community, and business preparedness plans.
Identify areas with repeated impacts to support safer decision-making around property, travel, and daily activities.
Access and download data to support local planning, research, and community resilience efforts.

Learn More about NOAA’s Industry Solutions

Architecture & Engineering

Overlay historical storm footprints onto project sites to inform structural design criteria and performance requirements.
Identify high-risk zones early in the planning process to reduce redesigns, construction delays, and cost overruns.
Select materials and construction methods based on documented hazard intensity and impact patterns.
Incorporate historical hazard data into siting and design decisions to improve long-term resilience and asset durability.

Learn More about NOAA’s Architecture and Engineering Solutions

Insurance & Reinsurance

Analyze intersections between insured assets and storm footprints to improve exposure verification and claims accuracy.
Use validated impact areas to streamline claims triage and reduce loss adjustment expenses.
Assess geographic risk concentration to inform underwriting and portfolio management strategies.
Enhance catastrophe models with historical footprint data to refine loss estimates and capital planning.
Identify repeat impact zones to support risk mitigation strategies and improve long-term loss outcomes.

Learn More about NOAA’s Insurance and Reinsurance Solutions

Retail

Map storm footprint data across store, warehouse, and distribution networks to reduce downtime and operational disruption.
Identify vulnerabilities in supply chains and transportation corridors to improve logistics planning and routing efficiency.
Align staffing, inventory, and contingency planning with historical impact patterns to strengthen operational preparedness.
Evaluate site selection and expansion strategies using historical hazard exposure to reduce long-term risk.
Minimize disruption-related losses and inefficiencies to support more resilient and cost-effective operations.

Learn More about NOAA’s Retail Solutions

Frequently Asked Questions

An event is an individual storm hazard. Examples include hail events and tornadoes.

Event intensity is determined based on the characteristics of each specific hazard type:

Tornadoes: Intensity is classified using the Enhanced Fujita (EF) scale, the same scale used in official reporting.
Hail: Intensity is categorized by hail size, grouped so users can distinguish areas of smaller versus larger hail. For more information, see How are hail events categorized?

Additional intensity metrics may be applied depending on the event category. Footprints display intensity in a way that matches each event type, providing a clear visual representation of storm severity.

Full definitions, including standardization methods, are provided in the Data Information Sheet.

EFC displays footprints for hail events with hail sizes of 0.5 inches and larger. Grouping hail into categories provides a consistent way to visualize and compare hail event intensity.

Hail events are grouped into the following size categories to help distinguish potential storm impacts:

0.5–1.0 inches
1.0–1.5 inches
1.5–2.0 inches
2.0–2.5 inches
2.5–3.0 inches
3.0–4.0 inches
Greater than 4.0 inches

Event footprints in the EFC are updated every 24 hours as new weather data becomes available. However, the speed at which an event appears depends on the type of event and the availability of source data:

Hail: Footprints are generated from radar-based datasets and are updated every 24 hours, typically appearing quickly once upstream data is processed.
Tornadoes: Footprints rely on official damage surveys conducted by National Weather Service forecast offices. These may take longer to appear due to reporting, verification, and quality-control workflows. Updates may be incorporated as source records are revised.

The EFC does not maintain an archival or historical version of prior updates. When source datasets are refreshed, they overwrite previous data files to ensure the catalog reflects the most current available information.

When data is not available for selected dates, it is because no source data exists for that period or the date falls outside the dataset’s coverage or update latency. In these cases, the application displays a message indicating: “There are no records available to display. Please try a different start or end date.”

Users can filter and explore events by:

Date range
Geographic location
Event type or category
Event characteristics such as hail size or tornado intensity

Results can be refined by interacting with the map, searching the event table, or applying column filters.

Information on the following is available in the Product Details section of the website:

What is an event footprint?
What information is included for each event?
What is the spatial coverage and resolution of EFC data?
How do I access the EFC data?
How do I use the EFC to find storm impacts and narratives?

Full definitions, including standardization methods is provided in the Data Information Sheet:

What data sources EFC uses
Product specifications
The update frequency
Data limitations and reliability
How event footprints are mapped

Yes. You can download event footprints, narratives, and metadata for individual events or as bulk datasets. Filtered results can be exported in formats such as GeoJSON for integration into GIS platforms and analytical workflows, or downloaded as CSV files.

Yes. The EFC data is designed to integrate with common geospatial tools and workflows, including GIS platforms such as ArcGIS and other analytics environments.

The EFC focuses on map-based, geospatial event footprints that show the physical extent of storm impacts. This allows users to directly visualize where hazards occurred and analyze spatial overlap with assets, infrastructure, or geographic areas. While the products below share underlying weather and climate information, they have different data structures and display methods.

The Storm Events Database provides tabular records of storm reports and characteristics, including descriptions, impacts, and metadata, but does not generate unified spatial footprint polygons.
The Damage Assessment Toolkit focuses on post-event damage survey data, primarily used to document and assess tornado damage paths rather than provide a harmonized multi-hazard footprint view.
The U.S. Precipitation Time Series Explorer provides time-series precipitation data for analyzing rainfall patterns over time, rather than event-specific impact footprints.

The outputs generated by the EFC are provided for informational and research purposes only. Users are responsible for independently evaluating the suitability of the information for their specific applications. NOAA does not guarantee that outputs from the EFC meet requirements for certification, regulatory approval, or legally binding determinations. The results should not be relied upon as a substitute for officially certified datasets, analyses, or professional judgment.

If you need officially certified event records, the Storm Events Database serves as the authoritative source for validated storm event information.

Source information for each dataset is provided within the application, and these are the best contacts for issues with data quality or structure:

NOAA has completed quality assurance and validation checks on this product. If you notice any discrepancies or issues, or would like to provide feedback to help improve the EFC product and support NOAA’s mission to deliver and disseminate information nationwide, please complete the product survey by selecting the Help improve this product button located at the bottom right of the EFC application.

Event Footprint Catalog

What is the Event Footprint Catalog?