History of Tornado warning in Timeline

A tornado warning is a crucial alert issued by weather agencies when a tornado has been sighted or indicated by radar, signaling imminent danger. These warnings prompt people in the affected area to seek immediate shelter. Early warnings are often facilitated by Doppler radar, which detects rotation within thunderstorms that can lead to tornado formation. Visual confirmation from weather spotters, the public, law enforcement, or emergency management is also a vital component in issuing warnings, especially in areas with limited radar coverage. These warnings are essential for saving lives and minimizing the impact of tornadoes.

April 1908: U.S. Weather Bureau Addresses Tornado Protection

In April 1908, the U.S. Weather Bureau published several replies regarding a question posed to the Weather Bureau on how to protect against tornadoes.

March 1925: Tri-State Tornado

In March 1925, the Tri-State Tornado, the deadliest tornado in U.S. history, occurred, resulting in death tolls well over 100 due to the lack of warnings.

1925: High Tornado Death Rate

In 1925, the tornado death rate in the United States was 1.8 deaths per million people per year.

1938: Weather Bureau Rescinds Ban on "Tornado" Usage

In 1938, the Weather Bureau rescinded its ban on the usage of the word "tornado" in weather products disseminated to emergency management personnel.

April 1947: Deadly Glazier–Higgins–Woodward Tornadoes

In April 1947, the Glazier–Higgins–Woodward tornadoes event had a death toll well over 100, contributing to a steady increase in the number of tornado-related fatalities through the 1950s due to the lack of warnings.

March 20, 1948: Tornado Strikes Tinker Air Force Base

On March 20, 1948, a tornado struck Tinker Air Force Base after an erroneous forecast of dry conditions. The storm produced wind gusts of 92 miles per hour and caused approximately $10 million in damage to military aircraft.

March 25, 1948: First Official Tornado Forecast

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

1948: USAF Pioneers Tornado Forecasting

In 1948, the USAF pioneered tornado forecasting and tornado warnings, restarting a debate over their reliability and whether military or civilian agencies should have jurisdiction over the issuance of weather warnings.

March 25, 1949: Successful Tornado Forecast by Miller and Fawbush

On March 25, 1949, Miller and Fawbush successfully predicted tornadic activity in southeastern Oklahoma.

July 12, 1950: Ban on Tornado Warnings Lifted

On July 12, 1950, Chief of Bureau Francis W. Reichelderfer officially lifted the ban on issuing tornado warnings to the general public. A Circular Letter was issued to all first order stations stating that "Weather Bureau employees should avoid statements that can be interpreted as a negation of the Bureau's willingness or ability to make tornado forecasts", and that a "good probability of verification" should exist when issuing such forecasts due to the difficulty in accurately predicting tornadic activity.

1951: Formation of the Severe Weather Warning Center

In 1951, the Air Force began issuing severe weather forecasts relayed to Weather Bureau offices and emergency personnel in tornado-prone regions through the formation of the Severe Weather Warning Center.

March 1952: Weather Bureau Issues 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 to become widely available for public consumption; however, a forecast issued the following evening managed to predict an outbreak of tornadoes across most of the warned seven-state area (from Texas to Indiana).

1954: First Televised Tornado Warning

In 1954, meteorologist Harry Volkman broadcast the first televised tornado warning over WKY-TV in Oklahoma City, against the Federal Communications Commission ban, believing it cost lives.

1974: Increase in Average Warning Times

In 1974, the average tornado warning times were -10 to -15 minutes.

1974: Tornado Alert discussed after Super Outbreak

The last tornado alert to be officially issued was discussed in earnest following the 1974 Super Outbreak.

1974: Use of tornado alert declined

Until the early 1980s, the National Weather Service defined an intermediate type of tornado advisory known as a tornado alert, indicating that tornado formation was imminent. The National Weather Service's use of this advisory began to decline after 1974.

May 3, 1999: First Tornado Emergency Declared

On May 3, 1999, the first tornado emergency was declared when an F5 tornado struck southern portions of the Oklahoma City metropolitan area, causing major damage exceeding $1 billion. The May 3, 1999 tornado was the event that triggered the first tornado emergency.

2000: Decline in Tornado Death Rate

In 2000, the tornado death rate in the United States declined to 0.11 per million people per year due to improvements in the tornado warning system.

September 20, 2002: Tornado Emergency Declared in Indianapolis

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

October 2007: Change in NWS Warning Issuance

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

2008: Emergency Management Ontario implements alert system

In 2008, Emergency Management Ontario implemented a system that issues red alerts for sections of the province under an Environment Canada-issued tornado warning. The system can sometimes override the tornado warning if local government or media outlets participate in the program. This system was implemented in 2008.

March 2012: Implementation of Impact Based Warning System

In March 2012, the NWS Weather Forecast Offices in Wichita and Topeka, Kansas, and Springfield, St. Louis and Kansas City/Pleasant Hill, Missouri, began incorporating categorical tornado and damage threat indicators for visually confirmed and radar-indicated tornadoes.

March 2013: Expansion of Threat and Damage Indicators

In March 2013, the NWS expanded the threat and damage indicators to 33 additional Central Region WFOs.

2013: Increased Warning Times and Reduced Death Toll

As of 2013, average tornado warning times have increased to about 15 minutes.

March 2014: Further Expansion of IBW Indicators

In March 2014, eight additional offices operating within the Eastern, Southern and Western Region divisions began using the IBW indicators.

2016: Agency-Wide Implementation of IBW Formatting

In 2016, the entire agency began using the IBW format for tornado warnings.

August 15, 2020: First Tornado Warning for Pyrocumulonimbus

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

July 2021: Full Implementation of IBW Formatting

In July 2021, 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 (R–MS) introduced the Tornado Observation Research Notification and Deployment to Operations (TORNADO) Act. The bill would establish a Hazard Risk Communication Office to propose improvements in the National Oceanic and Atmospheric Administration (NOAA)’s methods for predicting severe weather events and communicating weather alerts to the public.