Why We're Different From Every Other Weather Site
2-5 Minutes Faster
We get tornado warnings before they appear on other major weather websites and apps.
Real-Time Updates
We instantly show updates, cancellations, and extensions. Other sites only show the original warning.
🇺🇸 🇨🇦 Full Coverage
Complete tornado tracking for both the United States and Canada with real-time warnings from NWS and ECCC.
Critical Information Other Sites Miss
When meteorologists update a tornado warning with new information - like direction changes, speed updates, or area expansions - we show those changes immediately. Most weather sites never update their warnings at all, leaving you with outdated, potentially dangerous information.
See The Difference In Action
Watch this detailed explanation of how we deliver faster warnings and real-time updates that other weather sites miss.
Duration: 10 minutes | Learn about our real-time warning system and why speed matters
Table of Contents
Real-Time Warning Updates: What Other Sites Miss
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.
What Other Sites Do
- • Show only the ORIGINAL warning text
- • Never update when storm track changes
- • Miss cancellations (show expired warnings as active)
- • Ignore area expansions and extensions
- • No real-time storm movement information
- • Leave you with outdated, dangerous information
What Tornado Path Does
- • Show EVERY update in real-time
- • Instant storm track and speed changes
- • Immediate cancellation notices
- • Live area expansions and time extensions
- • Real-time storm movement vectors
- • Always current, life-saving information
Types of Updates We Track in Real-Time
Cancellations
When storms weaken or dissipate, we immediately remove them from active tracking
Extensions
Time extensions when storms persist longer than initially forecast
Track Changes
Direction and speed updates as storms evolve and move
Area Expansions
New counties and zones added as storms grow or change path
Severity Updates
Changes in threat level and storm characteristics
Confirmed Reports
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 immediately as they happen in both countries.
How We Get Tornado Warnings Faster
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 faster ways that emergency services have been using for years in both countries.
Standard Weather Apps
- • Use public NWS API (US) and ECCC feeds (Canada)
- • Data processed through multiple layers
- • 2-5 minute delay from issuance
- • Same as other major weather sites
- • Only get initial warnings - no updates!
Tornado Path
- • Direct NWS Open Interface (US) & ECCC CAP feeds (Canada)
- • Same feeds as emergency services in both countries
- • Warnings within 30 seconds of issuance
- • Redundant backup systems for reliability
- • Real-time updates, cancellations, and extensions!
Understanding US & Canadian Warning Systems
Both the United States and Canada operate sophisticated warning distribution systems, each with priority feeds for emergency services and public feeds for general consumption:
🇺🇸 US: NWS Open Interface (OI) - Priority System
This is the high-priority data feed that the NWS uses to distribute warnings to:
- Emergency Management Agencies
- 911 Dispatch Centers
- Emergency Alert System (EAS) broadcasters
- Wireless Emergency Alerts (WEA) systems
- Critical infrastructure operators
This system delivers warnings AND all updates within 15-30 seconds of a meteorologist hitting "send"
🇨🇦 Canada: ECCC CAP Alert System - Priority System
Environment and Climate Change Canada uses the CAP (Common Alerting Protocol) system to distribute warnings to:
- Provincial Emergency Management Organizations
- Municipal Emergency Services
- Alert Ready (wireless emergency alerts)
- Media outlets and broadcasters
- Critical infrastructure operators
CAP alerts include real-time updates, cancellations, and geographic polygon data within seconds of issuance
Public APIs - Standard Systems (Both Countries)
These are the public-facing APIs that most weather services use:
- Available to any developer or website
- Data goes through additional processing layers
- Includes formatting for public consumption
- Rate-limited to prevent server overload
- Often missing real-time updates and cancellations
These systems typically have a 2-5 minute delay and may not include all warning modifications
Why Every Second AND Every Update Counts
Tornado warnings provide an average of only 13 minutes of lead time. Getting warnings faster AND staying updated with changes can be the difference between safety and danger.
Speed Advantage
Those extra 2-5 minutes allow people to move from mobile homes to sturdy buildings, get to interior rooms on the lowest floor, or pull over safely if driving.
Update Advantage
Real-time 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.
How We Implement This Technology
Direct Priority System Connections
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.
Real-Time Processing
When any warning message is issued from either NWS or ECCC - whether new, updated, or cancelled - our systems receive and process the data within seconds. We parse warning details from both US and Canadian formats, track changes, and immediately update our live tracking map and alert systems.
Instant Distribution
All warning data from both countries - new, updated, extended, or cancelled - is immediately displayed to our website visitors through automatic updates, ensuring everyone sees the most current tornado warning information within 30 seconds of either the National Weather Service or Environment Canada issuing any change.
Redundancy and Reliability
While speed is crucial, reliability is equally important. We've built multiple layers of redundancy to ensure you never miss a tornado warning, even if our primary systems experience issues.
Primary Systems: NWS Open Interface & ECCC CAP Alerts
Our main data sources provide warnings AND all updates within 15-30 seconds of issuance from both countries. Both systems are monitored 24/7 and have built-in failover mechanisms.
Backup Systems: NWS Public API & ECCC Public Feeds
If our priority connections experience any issues, we automatically fall back to the standard public APIs for both countries. While this adds 2-5 minutes of delay, it ensures continuous warning coverage without any gaps in service.
Cross-Validation
We continuously cross-reference data from both sources to ensure accuracy and catch any potential discrepancies. This dual-source approach provides both speed and reliability.
Technical Specifications
Data Sources
- • NWS Open Interface (Primary - US)
- • ECCC CAP Alert System (Primary - Canada)
- • NWS API v1 (Backup - US)
- • ECCC Public Feeds (Backup - Canada)
- • VTEC (Valid Time Event Code) parsing (US)
- • CAP (Common Alerting Protocol) processing (Canada)
- • UGC (Universal Geographic Code) processing (US)
- • Real-time update processing (both countries)
Performance Metrics
- • 15-30 second warning delivery
- • Instant update processing
- • 99.9% uptime reliability
- • Real-time automatic updates
- • Automatic failover in <5 seconds
- • 24/7 system monitoring
Historical Tornado Data Sources
Our historical tornado database spans over 340 years, combining two comprehensive data sources to provide the most complete tornado record available anywhere online.
1680-1949: Thomas P. Grazulis Collection
Significant Tornadoes 1680-1991, a comprehensive research compilation by meteorologist Thomas P. Grazulis, digitized and made available by TornadoArchive.com.
Coverage Details:
- • F2+ tornadoes: Comprehensive records of all significant tornadoes
- • Deadly F0-F1 tornadoes: Included when fatalities occurred
- • Track precision: Historical tracks are approximate, based on documented start and end coordinates
- • Research methodology: Compiled from newspaper archives, local histories, weather bureau records, and eyewitness accounts
- • Geographic coverage: Primarily United States, with some Canadian records
- • Validation: Cross-referenced with multiple historical sources where available
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.
1950-Present: NOAA Storm Events Database
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:
- • All confirmed tornadoes: Complete records of EF0 through EF5 (F0-F5 before 2007)
- • Precise GPS tracks: Accurate beginning and ending coordinates for path mapping
- • Comprehensive metadata: Path length, width, peak intensity, damage estimates
- • Casualty records: Detailed direct and indirect injuries and fatalities
- • Damage assessments: Property and crop damage estimates (when available)
- • Survey verification: Each tornado verified by National Weather Service damage survey teams
- • Event narratives: Official descriptions and notable details from NWS meteorologists
- • Real-time updates: Database continuously updated as new tornadoes are confirmed and surveyed
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.
Data Quality & Accuracy
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.
Population Estimation Methodology
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.
How We Calculate Population Impact
Data Sources:
- • Google BigQuery Public Datasets: Official US Census Bureau data made available through Google Cloud
- • Geometry Data: Census block group boundaries from
bigquery-public-data.geo_census_blockgroups - • Population Data: American Community Survey 5-Year Estimates from
census_bureau_acs.blockgroup_2018_5yr
Calculation Method:
- Warning Polygon Received: When NWS issues a tornado warning or severe weather alert with a geographic polygon
- Block Group Intersection: Identify all US Census block groups that intersect with the warning area
- Weighted Overlap: Calculate what percentage of each block group falls within the warning polygon
- Population Weighting: Multiply each block group's population by its overlap percentage
- Sum Total: Add up all weighted populations to get the estimated total affected population
Accuracy & Granularity
Census Block Group Level:
- • Resolution: Block groups are the smallest geographic unit for which the Census Bureau publishes detailed demographic data
- • Size: Each block group typically contains 600-3,000 people (average ~1,000)
- • Coverage: Complete nationwide coverage across all 50 states
- • Precision: Provides highly accurate population estimates without compromising individual privacy
Weighted Intersection Approach:
Unlike simple boundary matching, our weighted intersection method provides more accurate estimates:
- • Partial Coverage: If 50% of a block group is in the warning area, we count 50% of its population
- • Geometric Precision: Uses spatial intersection calculations to determine exact overlap percentages
- • Urban vs Rural: Automatically accounts for population density variations across different areas
- • Real-Time Processing: Calculations happen within seconds of a warning being issued
What Warnings Include Population Estimates
Tornado Warnings
All active and historical tornado warnings since our system launched include population estimates for the warned area.
Severe Thunderstorm Warnings
Severe thunderstorm warnings with polygon data include population estimates for areas under threat.
Example Calculation
Tornado Warning for Oklahoma County, OK:
- Block Group A: 1,200 people, 80% inside warning polygon = 960 people
- Block Group B: 850 people, 100% inside warning polygon = 850 people
- Block Group C: 2,100 people, 45% inside warning polygon = 945 people
- Block Group D: 1,500 people, 20% inside warning polygon = 300 people
Total Estimated Population: 3,055 people
Important Notes
- • Estimates, Not Exact Counts: These are statistical estimates based on census data, not real-time counts of people in the area
- • Residential Population: Based on where people live, not where they may be during the day (workplace, school, etc.)
- • Time of Day: Actual population exposure varies by time (people at home vs. work/school)
- • Census Data Age: Uses most recent American Community Survey 5-year estimates
- • Continuous Updates: As census data is updated, we incorporate the latest population figures
See It In Action
Visit our live tornado tracking page to see current warnings and how we display real-time updates.
Live Tornado Tracker
