scholarly journals Tornado Warnings, Lead Times, and Tornado Casualties: An Empirical Investigation

2008 ◽  
Vol 23 (2) ◽  
pp. 246-258 ◽  
Author(s):  
Kevin M. Simmons ◽  
Daniel Sutter
Keyword(s):  
United States ◽  
Lead Time ◽  
Empirical Investigation ◽  
Conventional Wisdom ◽  
Lead Times ◽  
Time Intervals ◽  
Consistent Effect ◽  
Tornado Warnings ◽  
The Relationship

Abstract Conventional wisdom holds that improved tornado warnings will reduce tornado casualties, because longer lead times on warnings provide extra opportunities to alert residents who can then take precautions. The relationship between warnings and casualties is examined using a dataset of tornadoes in the contiguous United States between 1986 and 2002. Two questions are examined: Does a warning issued on a tornado reduce the resulting number of fatalities and injuries? Do longer lead times reduce casualties? It is found that warnings have had a significant and consistent effect on tornado injuries, with a reduction of over 40% at some lead time intervals. The results for fatalities are mixed. An increase in lead time up to about 15 min reduces fatalities, while lead times longer than 15 min increase fatalities compared with no warning. The fatality results beyond 15 min, however, depend on five killer tornadoes and consequently are not robust.

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.

Creativity Just in Time? The Role of Delivery Precision in Product Development

2015 ◽  
Vol 12 (05) ◽  
pp. 1550026
Author(s):  
Katarina Lund Stetler
Keyword(s):  
Product Development ◽  
Automotive Industry ◽  
Lead Time ◽  
Project Planning ◽  
Survey Study ◽  
Just In Time ◽  
Lead Times ◽  
The Creation ◽  
The Relationship

This paper presents the results from a quantitative survey study in the research and development (R&D) department of company in the automotive industry. The focus of the study has been on exploring the relationship between delivery precision and creativity. Given today's increasingly competitive market, companies must be able to both cut lead times and maintain high creativity and innovativeness in the organization. This study is an attempt to increase our understanding of how one means of cutting lead time, the imposition of high demands on delivery precision, is related to the creation of novel ideas in the industrialization phase of product development. The results point to an interesting relationship in which the imposition of high demands on delivery precision actually increases the perception of the creation of novel ideas. The results have implications for project planning and the role of time dedicated to exploratory tasks in product development.

Militias and the Iraqi State

2020 ◽  
pp. 100-118
Author(s):  
Idean Salehyan
Keyword(s):  
United States ◽  
Use Of Force ◽  
The United States ◽  
Conventional Wisdom ◽  
State Agents ◽  
Governance Strategy ◽  
The Government ◽  
The Military ◽  
The Relationship ◽  
Over Time

According to conventional wisdom, states have a monopoly on the legitimate use of force within their territories, and delegate its operation to closely held state agents such as the military and police. Yet when faced with insurgencies, states often enlist the support of paramilitary organizations or militias. The competence–control tradeoff is especially stark in these cases, as states depend on capable militias to fight insurgents, but also risk losing control over them. This chapter examines the tradeoff in light of the relationship between militia groups and the Iraqi government. To bring a semblance of security to Iraq, both the United States and the Iraqi government used paramilitary groups such as the Sons of Iraq and the Kurdish Peshmerga. Following the withdrawal of US troops, the government has become increasingly beholden to Shia militias, yet the case defies a simple, sectarian logic. This chapter examines the choice of governance strategy vis-à-vis militias in Iraq, and changes in that strategy over time, providing insights into the governor’s dilemma, counterinsurgency strategy, and state formation.

scholarly journals Eastern U.S. Verification of Ensemble Precipitation Forecasts

2017 ◽  
Vol 32 (1) ◽  
pp. 117-139 ◽  
Author(s):  
Sanjib Sharma ◽  
Ridwan Siddique ◽  
Nicholas Balderas ◽  
Jose D. Fuentes ◽  
Seann Reed ◽  
...  
Keyword(s):  
United States ◽  
Lead Time ◽  
Weather Prediction ◽  
The United States ◽  
Ensemble Forecast ◽  
Spatial Aggregation ◽  
Precipitation Forecast ◽  
Lead Times ◽  
Eastern United States ◽  
Skill Scores

Abstract The quality of ensemble precipitation forecasts across the eastern United States is investigated, specifically, version 2 of the National Centers for Environmental Prediction (NCEP) Global Ensemble Forecast System Reforecast (GEFSRv2) and Short Range Ensemble Forecast (SREF) system, as well as NCEP’s Weather Prediction Center probabilistic quantitative precipitation forecast (WPC-PQPF) guidance. The forecasts are verified using multisensor precipitation estimates and various metrics conditioned upon seasonality, precipitation threshold, lead time, and spatial aggregation scale. The forecasts are verified, over the geographic domain of each of the four eastern River Forecasts Centers (RFCs) in the United States, by considering first 1) the three systems or guidance, using a common period of analysis (2012–13) for lead times from 1 to 3 days, and then 2) GEFSRv2 alone, using a longer period (2004–13) and lead times from 1 to 16 days. The verification results indicate that, across the eastern United States, precipitation forecast bias decreases and the skill and reliability improve as the spatial aggregation scale increases; however, all the forecasts exhibit some underforecasting bias. The skill of the forecasts is appreciably better in the cool season than in the warm one. The WPC-PQPFs tend to be superior, in terms of the correlation coefficient, relative mean error, reliability, and forecast skill scores, than both GEFSRv2 and SREF, but the performance varies with the RFC and lead time. Based on GEFSRv2, medium-range precipitation forecasts tend to have skill up to approximately day 7 relative to sampled climatology.

scholarly journals Machine Learning for Real-Time Prediction of Damaging Straight-Line Convective Wind

2017 ◽  
Vol 32 (6) ◽  
pp. 2175-2193 ◽  
Author(s):  
Ryan Lagerquist ◽  
Amy McGovern ◽  
Travis Smith
Keyword(s):  
United States ◽  
Machine Learning ◽  
Lead Time ◽  
The United States ◽  
Skill Score ◽  
Learning System ◽  
Lead Times ◽  
Critical Success ◽  
Best Value ◽  
Straight Line

Abstract Thunderstorms in the United States cause over 100 deaths and $10 billion (U.S. dollars) in damage per year, much of which is attributable to straight-line (nontornadic) wind. This paper describes a machine-learning system that forecasts the probability of damaging straight-line wind (≥50 kt or 25.7 m s−1) for each storm cell in the continental United States, at distances up to 10 km outside the storm cell and lead times up to 90 min. Predictors are based on radar scans of the storm cell, storm motion, storm shape, and soundings of the near-storm environment. Verification data come from weather stations and quality-controlled storm reports. The system performs very well on independent testing data. The area under the receiver operating characteristic (ROC) curve ranges from 0.88 to 0.95, the critical success index (CSI) ranges from 0.27 to 0.91, and the Brier skill score (BSS) ranges from 0.19 to 0.65 (>0 is better than climatology). For all three scores, the best value occurs for the smallest distance (inside storm cell) and/or lead time (0–15 min), while the worst value occurs for the greatest distance (5–10 km outside storm cell) and/or lead time (60–90 min). The system was deployed during the 2017 Hazardous Weather Testbed.

US Strikes in Somalia and Targeted Civilian Killings by Al-Shabaab: An Empirical Investigation

2019 ◽  
Vol 15 (4) ◽  
pp. 589-603 ◽  
Author(s):  
Bryce W Reeder ◽  
John R Smith
Keyword(s):  
United States ◽  
Empirical Investigation ◽  
The United States ◽  
Current Policy ◽  
Policy Shift ◽  
Disaggregated Data ◽  
Human Costs ◽  
The Relationship

Abstract This study investigates the relationship between US strikes targeting Al-Shabaab and civilian victimization using spatially disaggregated data. We find that US strikes make it approximately 5.5 times more likely that civilians are murdered—an effect that is comparable to battles and periods of territorial loss. Disaggregating based on the target of each strike, however, reveals a more nuanced relationship: strikes that destroy Al-Shabaab military assets are associated with more civilian killings, whereas there is some evidence that strikes that kill members significantly reduce this form of violence. This implies an ability of the United States to continue current policy while also minimizing the human costs that directly result from intervention. Notably, however, this would require a policy-shift that avoids destroying Al-Shabaab's war-fighting capabilities, thereby reducing the ability of the United States to undermine the organization's capacity to wage war.

False Alarms, Tornado Warnings, and Tornado Casualties

2009 ◽  
Vol 1 (1) ◽  
pp. 38-53 ◽  
Author(s):  
Kevin M. Simmons ◽  
Daniel Sutter
Keyword(s):  
False Alarm ◽  
The United States ◽  
Probability Of Detection ◽  
False Alarms ◽  
Lead Times ◽  
Time Intervals ◽  
Standard Deviation Increase ◽  
False Alarm Ratio ◽  
Tornado Warnings ◽  
The Impact

Abstract This paper extends prior research on the societal value of tornado warnings to the impact of false alarms. Intuition and theory suggest that false alarms will reduce the response to warnings, yet little evidence of a “false alarm effect” has been unearthed. This paper exploits differences in the false-alarm ratio across the United States to test for a false-alarm effect in a regression model of tornado casualties from 1986 to 2004. A statistically significant and large false-alarm effect is found: tornadoes that occur in an area with a higher false-alarm ratio kill and injure more people, everything else being constant. The effect is consistent across false-alarm ratios defined over different geographies and time intervals. A one-standard-deviation increase in the false-alarm ratio increases expected fatalities by between 12% and 29% and increases expected injuries by between 14% and 32%. The reduction in the national tornado false-alarm ratio over the period reduced fatalities by 4%–11% and injuries by 4%–13%. The casualty effects of false alarms and warning lead times are approximately equal in magnitude, suggesting that the National Weather Service could not reduce casualties by trading off a higher probability of detection for a higher false-alarm ratio, or vice versa.

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