History of Tornado warning in Timeline

A tornado warning is issued when a tornado has been sighted or indicated by weather radar, signaling imminent danger. These warnings prompt individuals in the affected area to seek immediate shelter. Modern Doppler radar technology enables meteorologists to detect rotation within thunderstorms, providing early warning capabilities. However, visual confirmation from trained spotters, law enforcement, or the public remains critical, particularly when radar data is limited or unavailable. Ground truth observations are especially important because tornadoes can form in areas with poor radar coverage.

1925: Tornado Death Rate in 1925

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"

In 1938, the Weather Bureau rescinded its ban on using the word "tornado" in weather products for emergency management personnel.

April 1947: Glazier–Higgins–Woodward Tornadoes

In April 1947, the Glazier–Higgins–Woodward tornadoes contributed to the high death tolls from tornadoes due to lack of warnings.

March 20, 1948: Tornado Hits Tinker Air Force Base

On March 20, 1948, a tornado struck Tinker Air Force Base after an erroneous forecast of dry conditions. The tornado caused approximately $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: Pioneering Tornado Forecasting

In 1948, the USAF had pioneered tornado forecasting and tornado warnings.

March 25, 1949: Successful Tornado Forecast

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

July 12, 1950: Tornado Warning Ban Lifted

On July 12, 1950, Chief of the Weather Bureau, Francis W. Reichelderfer, officially lifted the ban on issuing tornado warnings to the general public in a Circular Letter. The letter emphasized the need for a "good probability of verification" when issuing such forecasts.

1951: Severe Weather Warning Center Formation

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: First Experimental Public Tornado Forecast

In March 1952, the Weather Bureau issued its first experimental public tornado forecast, which proved inaccurate but was followed by a successful forecast the next evening.

1954: First Televised Tornado Warning

In 1954, meteorologist Harry Volkman broadcast the first televised tornado warning over WKY-TV (now KFOR-TV) in Oklahoma City, defying the FCC ban. The warning was prompted by an alert issued by the USAF Severe Weather Warning Center, Volkman interrupted regular programming to warn viewers of a reported tornado approaching the Oklahoma City area.

1974: 1974 Super Outbreak and Tornado Alerts

Following the 1974 Super Outbreak, the last tornado alert to be officially issued was discussed, eventually leading to the elimination of tornado alerts due to the advent of Doppler weather radar.

1974: Tornado Alerts in 1974

In 1974, the National Weather Service used an intermediate tornado advisory called a tornado alert, indicating imminent tornado formation based on visible rotation in clouds. The use of tornado alerts 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 tornado emergency is a severe weather statement issued when a violent tornado poses a catastrophic risk.

2000: Tornado Death Rate in 2000

In 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.

September 20, 2002: Tornado Emergency in Indianapolis

On September 20, 2002, a tornado emergency was declared within the initial issuance of the tornado warning when an F3 tornado struck the Indianapolis, Indiana metropolitan area. This highlights that tornado emergencies can be declared during the initial warning based on the severity of the threat.

October 2007: Per-County Warning Basis

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

2008: Implementation of Emergency Alert System

In 2008, Emergency Management Ontario implemented a system of red alerts for sections of the province under an Environment Canada-issued tornado warning.

March 2012: Implementation of Impact Based Warning System

In March 2012, 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 as part of its implementation of a multi-tier Impact Based Warning (IBW) system.

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: Warning Times in 2013

As of 2013, the average tornado warning times had increased to about 15 minutes, with some cases extending to more than an hour.

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 IBW Adoption

In 2016, the entire agency began using the Impact Based Warning (IBW) format.

August 15, 2020: First Tornado Warning for Pyrocumulonimbus

On August 15, 2020, the National Weather Service issued its first tornado warning for a pyrocumulonimbus capable of producing a tornado in southeastern Lassen County, California, due to the Loyalton Fire.

July 2021: Full IBW Implementation

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 to improve severe weather prediction and communication.