scholarly journals Tornadoes without NWS Warning

2010 ◽  
Vol 25 (1) ◽  
pp. 159-172 ◽  
Author(s):  
J. Brotzge ◽  
S. Erickson
Keyword(s):  
Significant Proportion ◽  
Weather Forecast ◽  
The United States ◽  
Track Length ◽  
The Public ◽  
Sociological Factors ◽  
Tornado Warnings ◽  
County Population ◽  
Tornado Warning ◽  
Overall Ratio

Abstract During a 5-yr period of study from 2000 to 2004, slightly more than 26% of all reported tornadoes across the United States occurred without an NWS warning being issued. This study examines some of the reasons behind why no warnings were issued with these tornadoes, and what climatological, storm classification, and sociological factors may have played a role in the lack of warnings. This dataset of tornado records was sorted by F scale, geographically by region and weather forecast office (WFO), hour of the day, month of the year, tornado pathlength, tornado-to-radar distance, county population density, and number of tornadoes by day and order of occurrence. Results show that the tornadoes most likely to strike when the public is least likely to be aware were also those tornadoes with the greatest chance of not being warned. Singular tornado events (one tornado report per day within a WFO county warning area) and the first tornado report of the day were the most difficult scenarios on which to warn, with over half of all solitary tornado events not warned. Geographic areas that experienced a significant proportion of weak, solitary, and/or nocturnal tornadoes had a much higher ratio of missed warnings. In general, the stronger the tornado, as estimated from its F-scale rating and/or track length, the greater chance it was warned. However, the tornado distance from radar had a significant impact on tornado warning statistics. In addition, many weak tornadoes were not warned, and the overall ratio of missed tornado warnings to reported tornadoes actually increased over more densely populated regions, likely due to more complete postevent verification.

scholarly journals NWS Tornado Warnings with Zero or Negative Lead Times

2009 ◽  
Vol 24 (1) ◽  
pp. 140-154 ◽  
Author(s):  
J. Brotzge ◽  
S. Erickson
Keyword(s):  
Population Density ◽  
Lead Time ◽  
Large Scale ◽  
Weather Forecast ◽  
Sociological Factors ◽  
Tornado Warnings ◽  
County Population ◽  
Tornado Warning ◽  
Tornado Event ◽  
Difficult Challenge

Abstract During a 5-yr period of study from 2000 to 2004, slightly more than 10% of all National Weather Service (NWS) tornado warnings were issued either simultaneously as the tornado formed (i.e., with zero lead time) or minutes after initial tornado formation but prior to tornado dissipation (i.e., with “negative” lead time). This study examines why these tornadoes were not warned in advance, and what climate, storm morphology, and sociological factors may have played a role in delaying the issuance of the warning. This dataset of zero and negative lead time warnings are sorted by their F-scale ratings, geographically by region and weather forecast office (WFO), hour of the day, month of the year, tornado-to-radar distance, county population density, and number of tornadoes by day, hour, and order of occurrence. Two key results from this study are (i) providing advance warning on the first tornado of the day remains a difficult challenge and (ii) the more isolated the tornado event, the less likelihood that an advance warning is provided. WFOs that experience many large-scale outbreaks have a lower proportion of warnings with negative lead time than WFOs that experience many more isolated, one-tornado or two-tornado warning days. Monthly and geographic trends in lead time are directly impacted by the number of multiple tornado events. Except for a few isolated cases, the impacts of tornado-to-radar distance, county population density, and storm morphology did not have a significant impact on negative lead-time warnings.

scholarly journals A Preliminary Look at the Social Perspective of Warn-on-Forecast: Preferred Tornado Warning Lead Time and the General Public’s Perceptions of Weather Risks

2011 ◽  
Vol 3 (2) ◽  
pp. 128-140 ◽  
Author(s):  
S. Hoekstra ◽  
K. Klockow ◽  
R. Riley ◽  
J. Brotzge ◽  
H. Brooks ◽  
...  
Keyword(s):  
Lead Time ◽  
Stated Preference ◽  
The United States ◽  
Public Understanding ◽  
Lead Times ◽  
Present System ◽  
The Public ◽  
Tornado Warnings ◽  
Tornado Warning ◽  
Weather Risks

Abstract Tornado warnings are currently issued an average of 13 min in advance of a tornado and are based on a warn-on-detection paradigm. However, computer model improvements may allow for a new warning paradigm, warn-on-forecast, to be established in the future. This would mean that tornado warnings could be issued one to two hours in advance, prior to storm initiation. In anticipation of the technological innovation, this study inquires whether the warn-on-forecast paradigm for tornado warnings may be preferred by the public (i.e., individuals and households). The authors sample is drawn from visitors to the National Weather Center in Norman, Oklahoma. During the summer and fall of 2009, surveys were distributed to 320 participants to assess their understanding and perception of weather risks and preferred tornado warning lead time. Responses were analyzed according to several different parameters including age, region of residency, educational level, number of children, and prior tornado experience. A majority of the respondents answered many of the weather risk questions correctly. They seemed to be familiar with tornado seasons; however, they were unaware of the relative number of fatalities caused by tornadoes and several additional weather phenomena each year in the United States. The preferred lead time was 34.3 min according to average survey responses. This suggests that while the general public may currently prefer a longer average lead time than the present system offers, the preference does not extend to the 1–2-h time frame theoretically offered by the warn-on-forecast system. When asked what they would do if given a 1-h lead time, respondents reported that taking shelter was a lesser priority than when given a 15-min lead time, and fleeing the area became a slightly more popular alternative. A majority of respondents also reported the situation would feel less life threatening if given a 1-h lead time. These results suggest that how the public responds to longer lead times may be complex and situationally dependent, and further study must be conducted to ascertain the users for whom the longer lead times would carry the most value. These results form the basis of an informative stated-preference approach to predicting public response to long (>1 h) warning lead times, using public understanding of the risks posed by severe weather events to contextualize lead-time demand.

The History (and Future) of Tornado Warning Dissemination in the United States

2011 ◽  
Vol 92 (5) ◽  
pp. 567-582 ◽  
Author(s):  
Timothy A. Coleman ◽  
Kevin R. Knupp ◽  
James Spann ◽  
J. B. Elliott ◽  
Brian E. Peters
Keyword(s):  
Warning System ◽  
Specific Area ◽  
The United States ◽  
Digital Television ◽  
Public Officials ◽  
The Public ◽  
Tornado Warnings ◽  
Tornado Warning ◽  
Radio Broadcast ◽  
The U.S

Since the successful tornado forecast at Tinker AFB in 1948 paved the way for the issuance of tornado warnings, the science of tornado detection and forecasting has advanced greatly. However, tornado warnings must be disseminated to the public to be of any use. The Texas tornado warning conferences in 1953 began to develop the framework for a modern tornado warning system and included radar detection of tornadoes, a spotter network, and improved communications between the U.S. Weather Bureau, spotters, and public officials, allowing more timely warnings and dissemination of those warnings to the public. Commercial radio and television are a main source of warnings for many, and the delivery methods on TV have changed much since 1960. NOAA Weather Radio (NWR) was launched after the 1974 Super Outbreak of tornadoes, with the most important feature being the tone alert that allowed receivers to alert people even when the radio broadcast was turned off. Today, NWR reaches most of the U.S. population, and Specific Area Message Encoding technology has improved its warning precision. Outdoor warning sirens, originally designed for use in enemy attack, were made available for use during tornado warnings around 1970. “Storm based” warnings, adopted by the National Weather Service in 2007, replaced countybased warnings and greatly reduce the warning area. As communications advances continue, tornado warnings will eventually be delivered to precise locations, using GPS and other location technology, through cellular telephones, outdoor sirens, e-mails, and digital television, in addition to NWR.

scholarly journals Vulnerability due to Nocturnal Tornadoes

2008 ◽  
Vol 23 (5) ◽  
pp. 795-807 ◽  
Author(s):  
Walker S. Ashley ◽  
Andrew J. Krmenec ◽  
Rick Schwantes
Keyword(s):  
The United States ◽  
Past Century ◽  
Building Structures ◽  
The Public ◽  
Mobile Homes ◽  
The Past ◽  
High Fatality Rate ◽  
Potential Break ◽  
Tornado Warning ◽  
Dissemination System

Abstract This study investigates the human vulnerability caused by tornadoes that occurred between sunset and sunrise from 1880 to 2007. Nocturnal tornadoes are theorized to enhance vulnerability because they are difficult to spot and occur when the public tends to be asleep and in weak building structures. Results illustrate that the nocturnal tornado death rate over the past century has not shared the same pace of decline as those events transpiring during the daytime. From 1950 to 2005, a mere 27.3% of tornadoes were nocturnal, yet 39.3% of tornado fatalities and 42.1% of killer tornado events occurred at night. Tornadoes during the overnight period (local midnight to sunrise) are 2.5 times as likely to kill as those occurring during the daytime hours. It is argued that a core reason why the national tornado fatality toll has not continued to decrease in the past few decades is due to the vulnerability to these nocturnal events. This vulnerability is magnified when other factors such as escalating mobile (or “manufactured”) home stock and an increasing and spreading population are realized. Unlike other structure types that show no robust demarcation between nocturnal and daytime fatalities, nearly 61% of fatalities in mobile homes take place at night revealing this housing stock’s distinct nocturnal tornado vulnerability. Further, spatial analysis illustrates that the American South’s high nocturnal tornado risk is an important factor leading to the region’s high fatality rate. The investigation emphasizes a potential break in the tornado warning dissemination system utilized currently in the United States.

Measuring Tornado Warning Reception, Comprehension, and Response in the United States

2019 ◽  
Vol 11 (4) ◽  
pp. 863-880 ◽  
Author(s):  
Joseph T. Ripberger ◽  
Makenzie J. Krocak ◽  
Wesley W. Wehde ◽  
Jinan N. Allan ◽  
Carol Silva ◽  
...  
Keyword(s):  
United States ◽  
Performance Management ◽  
Source Code ◽  
The United States ◽  
Psychometric Tests ◽  
National Weather Service ◽  
Significant Development ◽  
Tornado Warnings ◽  
Tornado Warning ◽  
Information Domain

Abstract Social criteria are important to achieving the mission of the National Weather Service. Accordingly, researchers and administrators at the NWS increasingly recognize a need to supplement verification statistics with complementary data about society in performance management and evaluation. This will require significant development of new capacities to both conceptualize relevant criteria and measure them using consistent, transparent, replicable, and reliable measures that permit generalizable inference to populations of interest. In this study, we contribute to this development by suggesting three criteria that require measurement (forecast and warning reception, comprehension, and response) and demonstrating a methodology that allows us to measure these concepts in a single information domain—tornado warnings. The methodology we employ improves upon previous research in multiple ways. It provides a more generalizable approach to measurement using a temporally consistent set of survey questions that are applicable across the United States; it relies on a more robust set of psychometric tests to analytically demonstrate the reliability of the measures; and it is more transparent and replicable than previous research because the data and methods (source code) are publicly available. In addition to describing and assessing the reliability of the measures, we explore the sensitivity of the measures to geographic and demographic variation to identify significant differences that require attention in measurement. We close by discussing the implications of this study and the next steps toward development and use of social criteria in performance management and evaluation.

Anticipating Deviant Tornado Motion Using a Simple Hodograph Technique

2021 ◽  
Vol 36 (1) ◽  
pp. 219-235
Author(s):  
Cameron J. Nixon ◽  
John T. Allen
Keyword(s):  
Weather Forecast ◽  
Accurate Information ◽  
New Paradigm ◽  
Potential Predictability ◽  
Low Level ◽  
Tornado Warnings ◽  
Emergency Managers ◽  
Operational Forecasting ◽  
Median Error ◽  
Tornado Warning

AbstractThe paths of tornadoes have long been a subject of fascination since the meticulously drawn damage tracks by Dr. Tetsuya Theodore “Ted” Fujita. Though uncommon, some tornadoes have been noted to take sudden left turns from their previous path. This has the potential to present an extreme challenge to warning lead time, and the spread of timely, accurate information to broadcasters and emergency managers. While a few hypotheses exist as to why tornadoes deviate, none have been tested for their potential use in operational forecasting and nowcasting. As a result, such deviations go largely unanticipated by forecasters. A sample of 102 leftward deviant tornadic low-level mesocyclones was tracked via WSR-88D and assessed for their potential predictability. A simple hodograph technique is presented that shows promising skill in predicting the motion of deviant tornadoes, which, upon “occlusion,” detach from the parent storm’s updraft centroid and advect leftward or rearward by the low-level wind. This metric, a vector average of the parent storm motion and the mean wind in the lowest half-kilometer, proves effective at anticipating deviant tornado motion with a median error of less than 6 kt (1 kt ≈ 0.51 m s−1). With over 25% of analyzed low-level mesocyclones deviating completely out of the tornado warning polygon issued by their respective National Weather Service Weather Forecast Office, the adoption of this new technique could improve warning performance. Furthermore, with over 35% of tornadoes becoming “deviant” almost immediately upon formation, the ability to anticipate such events may inspire a new paradigm for tornado warnings that, when covering unpredictable behavior, are proactive instead of reactive.

scholarly journals The Relationship between Tornadic and Nontornadic Convective Wind Fatalities and Warnings

2011 ◽  
Vol 3 (1) ◽  
pp. 31-47 ◽  
Author(s):  
Alan W. Black ◽  
Walker S. Ashley
Keyword(s):  
Temporal Distribution ◽  
Initial Step ◽  
Severe Thunderstorm ◽  
The Public ◽  
High Magnitude ◽  
Tornado Warnings ◽  
Tornado Warning ◽  
Elevated Frequency ◽  
The Relationship ◽  
Warning Response

Abstract A database of tornado fatalities, nontornadic convective wind fatalities, severe thunderstorm warnings, and tornado warnings was compiled for the period 1986–2007 to assess the spatial and temporal distribution of warned and unwarned fatalities. The time of fatality and location as reported in Storm Data was compared to tornado and severe thunderstorm warnings to determine if a warning was in effect when the fatality occurred. Overall, 23.7% of tornado fatalities were unwarned, while 53.2% of nontornadic convective wind fatalities were unwarned. Most unwarned tornado fatalities occurred prior to the mid-1990s—coinciding with modernization of the National Weather Service—while unwarned nontornadic convective wind fatalities remained at a relatively elevated frequency throughout the study period. Geographic locations with high numbers of unwarned tornado and nontornadic convective wind fatalities were associated with one high-magnitude event that was unwarned rather than a series of smaller unwarned events over the period. There are many factors that contribute to warning response by the public, and the issuance of a severe thunderstorm or tornado warning is an important initial step in the warning process. A better understanding of the characteristics of warned and unwarned fatalities is important to future reduction of unwarned fatalities.

scholarly journals A 5-yr Climatology of Tornado False Alarms

2011 ◽  
Vol 26 (4) ◽  
pp. 534-544 ◽  
Author(s):  
J. Brotzge ◽  
S. Erickson ◽  
H. Brooks
Keyword(s):  
United States ◽  
Population Density ◽  
False Alarm ◽  
Late Summer ◽  
Weather Forecast ◽  
False Alarms ◽  
Combined Effects ◽  
Tornado Warnings ◽  
County Population ◽  
Geographic Regions

Abstract During 2008 approximately 75% of tornado warnings issued by the National Weather Service (NWS) were false alarms. This study investigates some of the climatological trends in the issuance of false alarms and highlights several factors that impact false-alarm ratio (FAR) statistics. All tornadoes and tornado warnings issued across the continental United States between 2000 and 2004 were analyzed, and the data were sorted by hour of the day, month of the year, geographical region and weather forecast office (WFO), the number of tornadoes observed on a day in which a false alarm was issued, distance of the warned area from the nearest NWS radar, county population density, and county area. Analysis of the tornado false-alarm data identified six specific trends. First, the FAR was highest during nonpeak storm periods, such as during the night and during the winter and late summer. Second, the FAR was strongly tied to the number of tornadoes warned per day. Nearly one-third of all false alarms were issued on days when no tornadoes were confirmed within the WFO’s county warning area. Third, the FAR varied with distance from radar, with significantly lower estimates found beyond 150 km from radar. Fourth, the FAR varied with population density. For warnings within 50 km of an NWS radar, FAR increased with population density; however, for warnings beyond 150 km from radar, FAR decreased regardless of population density. Fifth, the FAR also varied as a function of county size. The FAR was generally highest for the smallest counties; the FAR was ~80% for all counties less than 1000 km2 regardless of distance from radar. Finally, the combined effects of distance from radar, population density, and county size led to significant variability across geographic regions.

Verán ustedes las chozas más humildes. El discurso de pobreza en la diplomacia pública cardenista dirigida a Estados Unidos

2019 ◽  
Vol 35 (2) ◽  
pp. 255-281
Author(s):  
Sylvia Dümmer Scheel
Keyword(s):  
United States ◽  
New Deal ◽  
Public Diplomacy ◽  
The United States ◽  
The Public ◽  
The Poor ◽  
The Face ◽  
The Government ◽  
Lazaro Cardenas ◽  
The New Deal

El artículo analiza la diplomacia pública del gobierno de Lázaro Cárdenas centrándose en su opción por publicitar la pobreza nacional en el extranjero, especialmente en Estados Unidos. Se plantea que se trató de una estrategia inédita, que accedió a poner en riesgo el “prestigio nacional” con el fin de justificar ante la opinión pública estadounidense la necesidad de implementar las reformas contenidas en el Plan Sexenal. Aprovechando la inusual empatía hacia los pobres en tiempos del New Deal, se construyó una imagen específica de pobreza que fuera higiénica y redimible. Ésta, sin embargo, no generó consenso entre los mexicanos. This article analyzes the public diplomacy of the government of Lázaro Cárdenas, focusing on the administration’s decision to publicize the nation’s poverty internationally, especially in the United States. This study suggests that this was an unprecedented strategy, putting “national prestige” at risk in order to explain the importance of implementing the reforms contained in the Six Year Plan, in the face of public opinion in the United States. Taking advantage of the increased empathy felt towards the poor during the New Deal, a specific image of hygienic and redeemable poverty was constructed. However, this strategy did not generate agreement among Mexicans.

27. Immigration and other evils: A profile of Dr. C. K. Clarke and the eugenics movement in Canada

2007 ◽  
Vol 30 (4) ◽  
pp. 41
Author(s):  
L. Lee
Keyword(s):  
Mentally Ill ◽  
The United States ◽  
Cornell University ◽  
The Public ◽  
Canadian Population ◽  
Historical Figures ◽  
The Social ◽  
Eugenics Movement ◽  
The Government ◽  
Mental Defectives

Dr. C.K. Clarke (1857-1924) was one of Canada’s most prominent psychiatrists. He sought to improve the conditions of asylums, helped to legitimize psychiatry and established formal training for nurses. At the beginning of the 20th Century, Canada experienced a surge of immigration. Yet – as many historians have shown – a widespread anti-foreigner sentiment within the public remained. Along with many other members of the fledgling eugenics movement, Clarke believed that the proportion of “mental defectives” was higher in the immigrant population than in the Canadian population and campaigned to restrict immigration. He appealed to the government to track immigrants and deport them once they showed signs of mental illness. Clarke’s efforts lead to amendments to the Immigration Act in 1919, which authorized deportation of people who were not Canadian-born, regardless of how many years that had been in Canada. This change applied not only to the mentally ill but also to those who could no longer work due to injury and to those who did not follow social norms. Clarke is a fascinating example of how we judge historical figures. He lived in a time where what we now think of as xenophobia was a socially acceptable, even worthy attitude. As a leader in eugenics, therefore, he was a progressive. Other biographers have recognized Clarke’s racist opinions, some of whom justify them as keeping with the social values of his era. In further exploring Clarke’s interest in these issues, this paper relies on his personal scrapbooks held in the CAMH archives. These documents contain personal papers, poems and stories that proclaim his anti-Semitic and anti-foreigner views. Whether we allow his involvement in the eugenics movement to overshadow his accomplishments or ignore his racist leanings to celebrate his memory is the subject of ongoing debate. Dowbiggin IR. Keeping America Sane: Psychiatry and Eugenics in the United States and Canada 1880-1940. Ithaca and London: Cornell University Press, 1997. McLaren A. Our Own Master Race: Eugenics in Canada 1885-1945. Toronto: McClelland and Stewart, 1990. Roberts B. Whence They Came: Deportation from Canada 1900-1935. Ottawa: University of Ottawa Press, 1988.

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