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Reliable tornado data sourced from official organizations:
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Reliable tornado data sourced from official organizations:
We source tornado warnings directly from NWS and ECCC priority feeds — the same ones used by emergency services.
We show updates, cancellations, and extensions. Other sites only show the original warning.
Complete tornado tracking for both the United States and Canada with warnings from NWS and ECCC.
When meteorologists update a tornado warning with new information - like direction changes, speed updates, or area expansions - we show those changes. Most weather sites never update their warnings at all, leaving you with outdated, potentially dangerous information.
Here's the shocking truth: when the National Weather Service (US) or Environment Canada (Canada) updates a tornado warning, most weather websites never show those updates. They display the original warning and leave it unchanged until it expires, even when critical new information becomes available.
When storms weaken or dissipate, we remove them from active tracking
Time extensions when storms persist longer than initially forecast
Direction and speed updates as storms evolve and move
New counties and zones added as storms grow or change path
Changes in threat level and storm characteristics
When radar-indicated warnings become tornado-confirmed warnings
🚨 Real Example: What You Miss on Other Sites
US Example: A tornado warning is issued at 3:00 PM for a storm moving northeast. At 3:15 PM, the NWS updates the storm track to southeast toward a different town. At 3:25 PM, it's cancelled as the storm weakens.
Canadian Example: Environment Canada issues a tornado warning for southwestern Ontario at 2:00 PM. At 2:20 PM, they extend the warning to include additional counties. At 2:35 PM, they cancel the warning as the storm dissipates.
Other weather sites: Show only the original warnings until expiration, missing all updates.
Tornado Path: Shows every update as they happen in both countries.
Most weather websites and apps get their tornado warnings from the same sources: the National Weather Service's public API for the US and Environment Canada's public feeds for Canada. But there are other data sources that emergency services have been using for years in both countries.
Both the United States and Canada operate sophisticated warning distribution systems, each with priority feeds for emergency services and public feeds for general consumption:
This is the high-priority data feed that the NWS uses to distribute warnings to:
This system delivers warnings AND all updates directly from the source as they are issued
Environment and Climate Change Canada uses the CAP (Common Alerting Protocol) system to distribute warnings to:
CAP alerts include updates, cancellations, and geographic polygon data delivered directly from the source
These are the public-facing APIs that most weather services use:
These systems have additional processing layers and may not include all warning modifications
Tornado warnings provide limited lead time. Staying updated with changes to active warnings can be the difference between safety and danger.
Updates mean you know if a storm is moving toward or away from you, if new areas are at risk, or if the threat has been cancelled entirely.
We maintain direct connections to both the NWS Open Interface (US) and ECCC CAP alert system (Canada), the same systems that feed emergency services. This requires special authorization and technical infrastructure to handle both high-priority data streams simultaneously.
When any warning message is issued from either NWS or ECCC - whether new, updated, or cancelled - our systems receive and process the data. We parse warning details from both US and Canadian formats, track changes, and update our live tracking map and alert systems.
All warning data from both countries - new, updated, extended, or cancelled - is displayed to our website visitors through automatic updates, ensuring everyone sees the most current tornado warning information available.
Reliability is important. We've built multiple layers of redundancy to help ensure warning coverage, even if our primary systems experience issues.
Our main data sources provide warnings AND all updates directly from both countries' priority systems. Both systems are monitored 24/7 and have built-in failover mechanisms.
If our priority connections experience any issues, we automatically fall back to the standard public APIs for both countries. This ensures continuous warning coverage without any gaps in service.
We continuously cross-reference data from both sources to ensure accuracy and catch any potential discrepancies. This dual-source approach provides both accuracy and reliability.
Our historical tornado database spans over 340 years, combining two comprehensive data sources to provide the most complete tornado record available anywhere online.
Significant Tornadoes 1680-1991, a comprehensive research compilation by meteorologist Thomas P. Grazulis, digitized and made available by TornadoArchive.com.
Coverage Details:
Note: Historical tornado data becomes increasingly sparse before 1900 due to lower population density and limited record-keeping. Remote or wilderness tornadoes may not have been documented. Early records (1680s-1800s) are often limited to major, destructive tornadoes that were recorded in local histories or newspapers.
Official tornado records from NOAA's National Centers for Environmental Information (NCEI), maintained by the National Weather Service and local weather forecast offices across the United States.
Coverage Details:
Enhanced Fujita (EF) Scale implemented February 1, 2007, replacing the original Fujita (F) Scale with improved damage indicators and wind speed estimates. All pre-2007 ratings remain as originally assessed using F-Scale methodology.
1950-Present: Extremely high accuracy and completeness. Every confirmed tornado is documented with GPS coordinates and verified by NWS survey teams.
1900-1949: Good coverage of significant tornadoes (F2+) and all deadly tornadoes, though some weaker tornadoes in remote areas may not be documented.
1680-1899: Records are limited to notable, destructive tornadoes that were documented in newspapers, local histories, or weather records. Coverage is best in populated areas of the Eastern United States. Many tornadoes in sparsely populated regions during this period were likely never recorded.
For every tornado warning and severe weather alert, we calculate an estimated population impact to help you understand the potential scope of each threat. This data-driven approach uses official US Census data to provide accurate population estimates for affected areas.
bigquery-public-data.geo_census_blockgroupscensus_bureau_acs.blockgroup_2018_5yrUnlike simple boundary matching, our weighted intersection method provides more accurate estimates:
All active and historical tornado warnings since our system launched include population estimates for the warned area.
Severe thunderstorm warnings with polygon data include population estimates for areas under threat.
Tornado Warning for Oklahoma County, OK:
Total Estimated Population: 3,055 people
We are proud to be recognized by NOAA as a Weather-Ready Nation Ambassador — joining thousands of organizations committed to building a Weather-Ready Nation where communities are prepared and resilient against extreme weather events.
Weather-Ready Nation is a strategic outcome goal of the National Oceanic and Atmospheric Administration (NOAA) to build community resilience in the face of increasing vulnerability to extreme weather, water, and climate events. The initiative aims to have a society that is prepared for and responds to weather-dependent events.
The WRN Ambassador initiative formally recognizes organizations that share NOAA's commitment to building a Weather-Ready Nation. Ambassadors include businesses, emergency management agencies, schools, media outlets, and community organizations across the country — all working together to strengthen national resilience against extreme weather, water, and climate events.
With nearly 6,000 recognized ambassadors nationwide, this growing network represents a unified commitment to ensuring communities have the information and resources they need to stay safe during severe weather events.
Visit our live tornado tracking page to see current warnings and how we display updates.
Live Tornado Tracker