History of Tornado warning in Timeline

A tornado warning is issued when a tornado has been sighted or indicated by radar, posing an imminent threat to an area. These warnings prompt individuals to seek immediate shelter. Modern technology, especially Doppler radar, plays a crucial role in detecting rotation within thunderstorms, enabling early warnings. However, visual confirmation from weather spotters, the public, law enforcement, or emergency management remains vital, especially when radar data is unavailable or has gaps. These observations serve as critical ground truth, particularly in areas with limited radar coverage, ensuring timely alerts even when technology falls short.

March 1925: Tri-State Tornado

In March 1925, the Tri-State Tornado, the deadliest tornado in U.S. history, occurred, highlighting the devastating impact of tornadoes before widespread warning systems were in place.

1925: Tornado Death Rate

In 1925, the tornado death rate in the United States was 1.8 deaths per million people per year, highlighting the higher risk before widespread warning systems.

1938: Weather Bureau Rescinds Tornado Ban

In 1938, the U.S. Weather Bureau lifted its prohibition on using the word "tornado" in weather products that were shared with emergency personnel, marking a change in policy regarding tornado terminology.

April 1947: Glazier-Higgins-Woodward Tornadoes

In April 1947, the Glazier–Higgins–Woodward tornadoes caused significant devastation and high death tolls, illustrating the need for improved tornado warning systems.

March 20, 1948: Tinker Air Force Base Tornado

On March 20, 1948, a tornado struck Tinker Air Force Base after an erroneous forecast of dry conditions, causing an estimated $10 million in damages to military aircraft.

March 25, 1948: First Official Tornado Forecast

On March 25, 1948, the first official tornado forecast was made by United States Air Force Capt. Robert C. Miller and Major Ernest Fawbush.

1948: Early Tornado Forecasting History

Prior to 1948, the USAF pioneered tornado forecasting and warnings, although John P. Finley had developed experimental forecasts in 1885. Due to the unreliability of forecasts, there was a steady increase in tornado-related fatalities, as events prior to 1948 (such as the Tri-State Tornado in March 1925 and the Glazier–Higgins–Woodward tornadoes in April 1947) had death tolls well over 100.

March 25, 1949: Successful Tornado Prediction

On March 25, 1949, Miller and Fawbush successfully predicted tornadic activity in southeastern Oklahoma, marking another milestone in their forecasting efforts.

July 12, 1950: Tornado Warning Ban Officially Lifted

On July 12, 1950, Chief of Bureau Francis W. Reichelderfer officially revoked the ban on issuing tornado warnings to the general public, advising Weather Bureau employees to avoid statements negating the Bureau's ability to make tornado forecasts.

1951: Formation of Severe Weather Warning Center

In 1951, the Air Force established the Severe Weather Warning Center (SWWC) to disseminate severe weather forecasts to Weather Bureau offices and emergency personnel in tornado-prone regions, though the Weather Bureau later limited the release of tornado forecasts to military personnel due to jurisdictional concerns.

March 1952: First Experimental Public Tornado Forecast

In March 1952, the Weather Bureau issued its first experimental public tornado forecast, which proved inaccurate and was released too late for widespread public consumption.

1954: First Televised Tornado Warning

In 1954, meteorologist Harry Volkman broadcast the first televised tornado warning over WKY-TV in Oklahoma City, defying the FCC ban on broadcasting such warnings and leading to positive public feedback.

1974: Discussion after the 1974 Super Outbreak

Following the 1974 Super Outbreak, discussions were held regarding the last officially issued tornado alert.

1974: Decline of Tornado Alerts

In 1974, the National Weather Service began to decrease its reliance on tornado alerts, an intermediate advisory indicating imminent tornado formation. Despite this, tornado alerts remained present on public information materials from media outlets and NWS offices for about a decade afterward.

1974: Tornado Warning Times

In 1974, the average tornado warning times ranged from -10 to -15 minutes, indicating the challenges in providing timely alerts.

May 3, 1999: First Tornado Emergency Declared

On May 3, 1999, the first tornado emergency was declared when an F5 tornado struck southern Oklahoma City, resulting in significant damage exceeding $1 billion.

2000: Reduced Tornado Death Rate

By 2000, the tornado death rate in the United States had declined to 0.11 per million people per year, credited to improvements in the tornado warning system and increased reporting of severe weather.

September 20, 2002: Tornado Emergency in Indianapolis

On September 20, 2002, a tornado emergency was declared during the initial issuance of a tornado warning for an F3 tornado striking the Indianapolis, Indiana metropolitan area.

October 2007: Change in Warning Issuance

Prior to October 2007, the National Weather Service issued tornado warnings on a per-county basis.

2008: Implementation of Emergency Alert System in Ontario

In 2008, Emergency Management Ontario implemented a system to issue red alerts for areas under a tornado warning, highlighting the integration of provincial alerting systems.

March 2012: Implementation of Impact Based Warning System

In March 2012, NWS offices in Kansas and Missouri began incorporating categorical tornado and damage threat indicators for visually confirmed and radar-indicated tornadoes as part of the Impact Based Warning (IBW) system.

March 2013: Expansion of Threat and Damage Indicators

In March 2013, the NWS expanded the threat and damage indicators of the IBW system to 33 additional Central Region Weather Forecast Offices (WFOs).

2013: Increased Warning Times

As of 2013, average tornado warning times have increased to about 15 minutes, with lead times sometimes extending to more than an hour, showcasing advancements in forecasting technology.

March 2014: Further Expansion of IBW Indicators

In March 2014, eight additional NWS offices operating within the Eastern, Southern and Western Region divisions began using the Impact Based Warning (IBW) indicators.

2016: Agency-Wide Use of IBW Format

In 2016, the entire National Weather Service (NWS) agency began using the Impact Based Warning (IBW) format for tornado warnings.

August 15, 2020: Tornado Warning for Pyrocumulonimbus

On August 15, 2020, the National Weather Service issued a tornado warning for a pyrocumulonimbus cloud capable of producing a tornado in southeastern Lassen County, California, affected by the Loyalton Fire.

July 2021: Full Implementation of IBW Formatting

In July 2021, Impact Based Warning (IBW) formatting was fully implemented for other individual warning bulletins when all NWS offices incorporated damage threat indicators into severe thunderstorm warnings.

April 2023: Introduction of the TORNADO Act

In April 2023, U.S. Sen. Roger Wicker introduced the Tornado Observation Research Notification and Deployment to Operations (TORNADO) Act, aimed at improving NOAA's severe weather prediction and communication methods.