Tornado Struck Research Articles

Intended Response to Tornado Watches among Tennessee Residents

Abstract Tornado watches are issued by the National Weather Service when conditions are favorable for tornado formation. Individuals’ responses to a tornado watch may affect their ability to seek shelter before a tornado strikes. Here, survey data of Tennessee residents were used to determine common patterns in intended responses to two tornado watch scenarios: one during daytime, and the other at nighttime. Three common patterns were identified for a daytime watch: doing nothing, seeking information using technology, or seeking shelter and praying for safety. The two patterns for a nighttime watch were either to do nothing or to react actively by seeking further information, seeking shelter, and contacting friends and family. Logistic regressions indicated younger participants, those with prior tornado experience, and those who understood a tornado watch were less likely to intend to seek shelter and pray for safety during the daytime. Older participants and those without strong self-efficacy beliefs were less likely to use technology to find further information. For the nighttime scenario, participants living in east Tennessee and those who believed that bodies of water provide protection from tornadoes were more likely to respond actively, while wealthier participants and those living in single- or multifamily houses were less likely to respond actively. These results show that intended watch response is influenced by many factors, including age, income, and self-efficacy beliefs, as well as knowledge of and experience with tornadoes. In addition, those who do not understand the meaning of a tornado watch may be more likely to seek shelter prematurely. Significance Statement We sought to determine common intended responses to tornado watches, a type of alert that indicates conditions are favorable for tornadoes over the next few hours, among the public. We then analyzed which participant characteristics were associated with these common response types. Age, income, housing type, belief in tornado myths, knowledge of watch terminology, and belief that one’s own actions affect tornado survival likelihood were all significantly associated with common response types. These findings are important for forecasters, broadcasters, and others responsible for alerting the public for severe weather. Clarifying tornado watch terminology, dispelling myths, and specifying where those in mobile homes can find shelter are all important strategies for a better-prepared public.

Reliability of a structure stricken by a tornado

A tornado may become a very dangerous climatic action for any structure, depending on the tornado intensity and extent of the structure. The origin of a tornado, its range and further activity appear to be unpredictable and completely random. The strike of a tornado to a structure depends on the tornado movement and the structure extent. The tornado intensity is specified by the wind speed, following observed damages and consequences. The probability of a tornado strike on a structure depends on the extent of the structure itself, on the tornado range, and the extent of the considered reference area, for which data concerning tornado appearance are available. The probability of failure of a structure is given by the product of the probability of contact of a tornado with the structure and the probability of exceeding the design speed of the tornado wind. The probability of exceeding the design wind speed depends on the assumed distribution of wind speed and the frequency of tornadoes during the required lifetime of the structure. The target failure probability of common structures presented in available documents is 10−6 per year, and 10−7 per year of structures in power plants. However, it is not clear how these criteria have been derived. Further development of reliability theory of tornado-stricken structures is recommended to be focused on the risk analysis of appropriate systems, of which the considered structures are elements, on the target failure probability, on detailed analysis of the probability distribution of tornado wind speed and their frequency during the required lifetime of the structures.

Statistics Show Value in Old‐School Crop Condition Reports

Statistics Show Value in Old‐School Crop Condition Reports

First-Decade Biomass and Carbon Accumulation, and Woody Community Change after Severe Wind Damage in a Hemlock-White Pine Forest Remnant

Studies of biomass and carbon dynamics and community composition change after forest wind disturbance have predominantly examined trends after low and intermediate severity events, while studies after very severe wind disturbance have been few. This study documents trends in aboveground biomass and carbon across 10 years of forest recovery after severe wind disturbance. In July 1989, a tornado struck mature Tsugacanadensis-Pinusstrobus forest in northwest Connecticut, USA, causing damage across roughly 8 ha. Canopy tree damage and regeneration were surveyed in 1991 and 1999. Two primary hypotheses were tested, both of which derive from regeneration being primarily via the release of suppressed saplings rather than new seedling establishment: (1) Biomass and carbon accumulation will be faster than accumulation reported from a similar forest that experienced similar severity of wind disturbance; and (2) The stand will experience very little change in species composition or diversity. Estimated immediate post-disturbance (1989) aboveground live-tree carbon was 20.7 ± 43.9 Mg ha−1 (9.9% of pre-disturbance) Ten years after the disturbance, carbon in aboveground live tree biomass increased to 37.1 ± 47.9 Mg ha−1; thus for the first decade, annual accumulation averaged 1.6 Mg ha−1 of carbon; this was significantly faster than the rate reported in a similar forest that experienced similar severity of wind disturbance. The species diversity of woody stems ten years after the disturbance was significantly higher (nonoverlapping confidence intervals of rarefaction curves) than pre-disturbance canopy trees. Thus, hypothesis 1 was confirmed while hypothesis 2 was rejected. This study augments the limited number of longer-term empirical studies that report biomass and carbon accumulation rates after wind disturbance, and can therefore serve as a benchmark for mechanistic and modeling research.

Engineering-Based Tornado Damage Assessment: Numerical Tool for Assessing Tornado Vulnerability of Residential Structures

Following a series of deadly tornadoes between 2011, this paper develops a numerical tool to help communities better predict and quantify the potential tornado damage to single-family residential structures from a tornado strike. The objective is to determine the predictive capability of an engineering-based tornado damage-assessment (ETDA) Tool using published building damage observations captured by the authors in two recent tornadoes. The research is motivated by the need for the public to visualize the extent of tornado vulnerabilities of residential buildings in our communities. The research developed a numerical estimation model to aggregate damage that a specified tornado would cause to the residential wood-framed structures in a community. The ETDA Tool was developed around a Monte Carlo simulation engine, using theoretical models for tornado wind velocity and pressure drop in the tornado vortex, as well as experimentally-determined probability distribution functions for the structural resistances of eight building component systems selected to describe the structure. The output of the EDTA Tool is presented as series of mean damage ratios, and other statistics quantifying tornado-damage caused plotted against distance away from the tornado vortex centerline. The paper explains the methodology of the approach and present results comparing hindcast damage ratios against observed values of field-observations collected after a tornado strike on residential communities in Garland/Rowlett, TX. It was found the ETDA Tool provides reasonable agreement with the field damage observations to houses. The Tool could be used by a community to model any tornado path and/or size and estimate future damage. More research to further our understanding of tornado-induced wind loads and wind-borne debris effects are needed to increase confidence in its application to any tornado and any city.

Temporal discounting of tornado shelter-seeking intentions amidst standard and impact-based weather alerts: A crowdsourced experiment.

Tornadoes are atmospheric events capable of massive devastation, involving physical destruction and human casualties. Following the 2011 Joplin, MO tornado that claimed the lives of nearly 160 people, the National Weather Service and National Institute of Standards and Technology concluded that better warning systems would have saved lives. This conclusion prompted the creation of impact-based warning (IBW) messages that use explicit language to convey damage threats and potential outcomes. The current study examined the efficacy of impact-based warnings for evoking shelter-seeking intentions in a simulated tornado event. We stratified participants recruited through a crowdsourcing service into 1 of 4 simulated tornado warning conditions, varying with respect to the content and description (IBW) provided. Participants rated their likelihood of immediate shelter-seeking given increasing lead times to the potential tornado strike. Analyses indicated that participants receiving IBW maintained shelter-seeking most across increasing delays. Results suggest viable warning delivery at longer lead times when employing IBW, thereby providing more preparation while bypassing risks of delay-induced inaction. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The One and Only Bob by Katherine Applegate

Reviewed by: The One and Only Bob by Katherine Applegate Kate Quealy-Gainer, Assistant Editor Applegate, Katherine The One and Only Bob; illus. by Patricia Castelao. Harper, 2020 [352p] Trade ed. ISBN 978-0-06-299131-7 $18.99 E-book ed. ISBN 978-0-06-299133-1 $10.99 Reviewed from galleys R Gr. 3-5 In this sequel to her Newbery-winning The One and Only Ivan (BCCB 2/12), Applegate shifts the narration from the gorilla Ivan to his best pal Bob, an irascible street mutt who has now been thoroughly domesticated by the zookeeper’s daughter, Julia. Bob’s always thrilled when Julia takes him on a visit to the zoo to see Ivan and their baby elephant friend, Ruby, but one outing takes a dangerous turn when a tornado strikes, separating Julia and Bob, destroying several animal habitats, including Ivan’s, and throwing the zoo into chaos. As Bob searches for his friends, he narrowly escapes danger, makes a few daring saves, and comes face to face with one of the more painful secrets of his life. Much like Bob himself, this book has an appealing mix of frenetic energy and somber contemplation, and the lightning-quick pace (most of the book takes place in the few hours before and after the storm) is tempered by Bob’s flashbacks to his time as a stray, scrapping for food and often seeing the worst in both animals and humans. The mutt’s happy-go-lucky demeanor is belied by quiet pauses of reflection, touched by pain and grief (“There are so many ways the world can find to fail you”), and even the upbeat resolution to his secret comes with its own sorrow. A secondary cast of animals, ranging from a sassy squirrel to a snobby poodle, provides bits of humor, and the rescue scenes add drama and thrills. Commentary on animal welfare and climate change is carefully woven into the narrative, giving readers food for thought but never overwhelming what is ultimately a tale of friendship and forgiveness. Copyright © 2020 The Board of Trustees of the University of Illinois

Training Emergency Department Charge Nurses Through Tabletop Exercises

Introduction:In a disaster or mass casualty incident, the Emergency Department (ED) charge nurse is thrust into an expanded leadership role, expected to not only manage the department but also organize a disaster response. Hospital emergency preparedness training programs typically focus on high-level leadership, while frontline decision-making staff get experience only through online training and infrequent full-scale exercises. Financial and time limitations of full-scale exercises have been identified as major barriers to frontline training.Aim:To discuss a cost-effective approach to training ED charge nurses and informal leaders in disaster response.Methods:A formal training program was implemented in the ED. All permanent and relief charge nurses are required to attend one four-hour Hospital ICS course within their first year in their position, as well as participate in a minimum of one two-hour ED-based tabletop exercise per year. The tabletop exercises are offered bimonthly, covering various mass casualty scenarios such as apartment complex fires, riots, and a tornado strike. Full-scale exercises involving the ED occur annually.Results:ED permanent and relief charge nurses expressed increased skills and knowledge in areas such as initiation of disaster processes, implementation of hospital incident command, and familiarization with protocols and available resources. Furthermore, ED charge nurses have demonstrated strong leadership, decision-making, and improved response to actual mass casualty incidents since implementing ICS training and tabletop exercises.Discussion:Limitations of relying on full-scale disaster exercises to provide experience to frontline leaders can be overcome by the inclusion of ICS training and tabletop exercises for ED charge nurses in a hospital training and exercise plan. Implementing a structured training program for ED charge nurses focusing on leadership in mass casualty incidents is one step to building a more resilient and prepared ED, hospital, and community.

The Finger of God

The Finger of God Melissa Faliveno (bio) You have not come to a mountain that can be touched and that isburning with fire; to darkness, gloom and storm.hebrews 12:18 It was a warm night in early June—the Midwestern kind of warm specific to spring, the air so thick it's hard to breathe, so wet it feels as if you're swimming—when a tornado struck and destroyed a small town just eight miles west of mine. I was a little over a year old. My mother, who was younger than I am now, came into my bedroom as I slept and looked out the window into the darkness of the west. It was the same window out of which I would look for years to come, whenever the clouds began to build—face and fingers pressed to glass, cranking open the pane to get a better look at the sky. But that night, it was my mother who watched. She looked at the clock and waited. It was just after 11 pm. Maybe the wind was howling. Maybe there was thunder. Maybe, more likely, there was only silence—that still, strange calm Midwesterners know so well, the kind that precedes the most violent of storms. And then she saw them: fast, bright sparks of green, a second or two apart, like flash bulbs in the distance against the dark. It would take her a minute to realize what she was seeing: a massive tornado, invisible in the black of night, striking each pole of the power lines that ran along the highway—the road that connected a small doomed town and our own. Soon she would pick me up, press my small body to her chest, and hurry us down to the room beneath the stairs, a tiny crawlspace where we would huddle together—my father and the cat crammed in with us—and wait out the storm. But for a second or two she stood there in the dark, looking out into the night, as a great, unstoppable force tore through a sleeping town, destroying everything in its path. It was June 8, 1984. The town was called Barneveld, and the tornado—the largest in Wisconsin history—was an f5. On the Fujita scale, the f5 is [End Page 172] the largest, rarest, and most powerful tornado. It carries winds of more than two hundred miles per hour and can stretch up to a mile in width. It has the ability to rip entire houses off their foundations, pluck trees and trucks and livestock from the land and toss them to the sky. The f5 is dangerous, unpredictable, and unforgiving. In the bad nineties action movie Twister, which I watched obsessively as a kid, a group of storm chasers—led by the late Bill Paxton and an unhinged Helen Hunt—pause around a dinner table, on a momentary break from their mission in the Kansas stretch of Tornado Alley, when someone asks what an f5 is like. Commotion at the table ceases; conversation comes to a dramatic halt; forks are placed gravely onto plates. One of the elder chasers on the team, a character nicknamed "Preacher," stops as he serves up a steak. He takes a breath and says: It's the finger of God. I grew up in a small, God-fearing town in southern Wisconsin called Mount Horeb. A blue-collar place dealing in livestock feed and John Deere tractors, with a population back then of just over two thousand, Mount Horeb is perched on a high, sloping hill, surrounded on all sides by long, rolling fields of corn and wheat and soy. Five miles to the west are the Blue Mounds, a state park and tourist attraction that keeps the area on the map: a stretch of low, tree-dotted hills—technically monadnocks, or small mountains, a geological anomaly in that part of the country—with caves beneath them, a line of squat blue peaks that as children we were told protected our little town like a castle's defensive wall. From storms and monsters, the spirits that dwelt in the caves; from whatever else might come our way...

Post-traumatic growth 2.5 years after the 2011 Joplin, Missouri tornado

ABSTRACTIn 2011 a major tornado struck Joplin, Missouri, killing 158 and injuring 1,150 individuals. Approximately 2.5 years after this disaster, an online survey of Joplin adult residents (N = 438) was conducted to examine the relationship between disaster experience, post-traumatic stress (PTS) symptoms, communication with family, friends, and neighbors, and post-traumatic growth (PTG). Results indicate that more tornado exposure and tornado PTS symptoms were related to more PTG. In addition, engaging in more communication about the tornado with family, friends, and neighbors was related to more perceived PTG. Implications for social work practice in long-term post-disaster communities include building upon areas of growth and promoting positive interpersonal connections among survivors.

Post-storm damage surveys of tornado hazards in Canada: Implications for mitigation and policy

Tornadoes have the potential to cause significant destruction and loss of life in many regions across Canada. Accordingly, these hazards are essential to consider for a comprehensive emergency management plan. Following a suspected tornadic event, damage surveys are conducted by Environment Canada to determine the extent and severity of damage in order to assign an Enhanced Fujita scale rating. The purpose of this paper is to investigate the process involved in conducting storm damage surveys, and to assess how information gathered during these surveys is used. Primary research for this study involved conducting semi-structured interviews with Environment Canada damage surveyors from various provinces (n=10) and wind engineering researchers from a large public university in Canada (n=2), as well as an onsite observation of a damage survey conducted in Angus, Ontario after a tornado struck on 17 June 2014. The results of this study underscored the subtle but important differences between storm damage surveys conducted in the United States and Canada. It was also found that the majority of damage surveys are now conducted remotely through photos, videos, and telephone interviews with key witnesses. Finally, damage surveys were found to be a critical component of the disaster management cycle by contributing to both risk reduction and preparedness. Introducing sophisticated technologies such as mobile devices and applications, as well as using volunteered geographic information to display damage reports on a web-map, could further improve the damage surveying process in both Canada and abroad.

Predictors of compliance with tornado warnings issued in Joplin, Missouri, in 2011.

Joplin, a city in the southwest corner of Missouri, United States, suffered an EF-5 tornado in the late afternoon of 22 May 2011. This event, which claimed the lives of 162 people, represents the deadliest single tornado to strike the US since modern record-keeping began in 1950. This study examines the factors associated with responses to tornado warnings. Based on a post-tornado survey of survivors in Joplin, it reveals that tornado warnings were adequate and timely. Multivariate logistic regression identified four statistically significant determinants of compliance with tornado warnings: number of warning sources, whether respondents were at home when the tornado struck, past tornado experience, and gender. The findings suggest several recommendations, the implementation of which will further improve responses to tornado warnings.

Empirically Based Probabilistic Tornado Hazard Analysis of the United States Using 1973–2011 Data

Tornadoes are one of the most devastating natural hazards that occur in the United States. Although the average number of tornadoes per year across the country is approximately 1,200, the annual likelihood of experiencing a tornado at a particular location is quite small due to their relatively small size. However, the high consequence of a tornado strike necessitates the determination of geographic tornado hazard. This paper presents a methodology to estimate the annualized probabilistic tornado hazard over the contiguous United States based upon the most recent 38 years of climatological tornado data. Furthermore, with the use of detailed damage surveys after the April 3–4, 1974 and April–May 2011 tornado outbreaks, an empirical method was developed and applied to account for the gradient of wind speed along a tornado’s path length and path width. From this, a probabilistic tornado hazard index can be developed across the United States and can eventually be extended to tornado hazard for any location.

Prevention Plan to Save Human Life, by Building Safe Monolithic Dome or EcoShell Structures

The purpose of our study is to evaluate, monolithic houses that were popular thirty and forty years ago. The world as a whole understands the use of Monolithic Domes and EcoShells. According to a non-profit group Domes for the World Foundation whose mission is for helping people to help themselves by building safe Monolithic Dome or EcoShell structures. Dome structures are being built around the world in much needed areas. They save lives everywhere and can save human life in the United States. Every few months, news brings another tornado that destroyed property or took away human life. In 2012, a Christmas day tornado struck Mobile, Alabama. Tornados are not a seasonal event so buildings and structures for tomorrow need a prevention plan to save life and housing destruction. It is time to examine a monolithic dome structure which meets the prevention plan from storm and tornado destruction. Today, we know much more about tornados. Almost every large tornado near a city has a good chance of being filmed. Thirty and forty years ago, very little coverage was filmed until after the storm when everyone was picking up the pieces. Today, more people have dash cams and cell phones that can record video. The 21st century brought technology to almost everyone and it is possible to see filmed video of a tornado shortly after it strikes.

Experimental Flight Testing of Night Vision Imaging Systems in Military Fighter Aircraft

Abstract This paper describes the research and experimental flight test activities conducted by the Italian Air Force Official Test Centre (RSV), in collaboration with Alenia Aermacchi and Cranfield University, in order to confer night vision imaging systems (NVIS) capability to the Italian TORNADO Interdiction and Strike and Electronic Combat and Reconnaissance aircraft. The activities included design, development, test, and evaluation activities, including night vision goggle (NVG) integration, cockpit instruments, and external lighting modifications, as well as various ground test sessions and a total of 18 flight test sorties. RSV and Litton Precision Products were responsible for coordinating and conducting the installation of the internal and external lights. Particularly, an iterative process was established allowing in-site rapid correction of the major deficiencies encountered during the ground and flight test sessions. Both single-ship (day/night) and formation (night) flights were performed, with testing activities shared among the test crews involved, allowing for a redundant examination of the various test items by all participants. An innovative test matrix was developed and implemented by RSV for assessing the operational suitability and effectiveness of the various modifications implemented. Also important was the definition of test criteria for Pilot and Weapon Systems Officer workload assessment during the accomplishment of various operational tasks during NVG missions. Furthermore, the specific technical and operational elements required for evaluating the modified helmets were identified, allowing an exhaustive comparative evaluation of the two proposed solutions (i.e., HGU-55P and HGU-55G modified helmets). The initial compatibility problems encountered were progressively mitigated by incorporating modifications in both front and rear cockpits at various stages of the test campaign. This process allowed considerable enhancement of the TORNADO NVIS configuration, giving good medium- to high-level NVG operational capability to the aircraft. Further developments also include the internal/external lighting for the Italian TORNADO “Mid-Life Update” and other programs such as AMX aircraft internal/external light modification/testing and the activities addressing low-altitude NVG operations with fast jets (e.g., TORNADO, AMX, MB-339CD), with a major issue being the safe ejection of aircrew with NVG and NVG modified helmets. Two options have been identified for solving this problem, namely, the modification of the current Gentex HGU-55 helmets and the design of a new helmet incorporating a reliable NVG connection/disconnection device (i.e., a mechanical system fully integrated in the helmet frame) with embedded automatic disconnection capability in case of ejection. Other relevant issues to be accounted for in these new developments are the helmet dimensions and weight, the NVG usable field of view as a function of eye-relief distance, and the helmet's center of gravity (moment arms) with and without NVG (effect on aircrew fatigue during training and real operational missions).

Response and Recovery after the Joplin Tornado: Lessons Applied and Lessons Learned

An EF-5 Tornado struck Joplin, MO on May 22, 2011, leaving a twenty mile long path of destruction in its wake. An estimated 7,500 homes and over 500 businesses were damaged or destroyed, with damage estimated at up to $3 billion. Joplin has seen a rapid recovery despite the extensive damage. The Joplin tornado provides a valuable opportunity to determine if findings from the aftermath of Hurricane Katrina apply to other major natural disasters. This study uses interviews with various government officials, church leaders, charities, business owners, and homeowners, as well as conventional data, to examine the response and recovery efforts in Joplin. We argue that Joplin’s rapid recovery is a result of Federal, state and local officials letting the voluntary sector, including businesses, national charities, churches, and local community groups, lead the response and recovery.

A New Avionics-Based GNSS Integrity Augmentation System: Part 2 – Integrity Flags

This paper presents the second part of the research activities carried out to develop a novel Global Navigation Satellite System (GNSS) Avionics-Based Integrity Augmentation (ABIA) system for manned and Unmanned Aerial Vehicle (UAV) applications. The ABIA system's architecture was developed to allow real-time avoidance of safety-critical flight conditions and fast recovery of the required navigation performance in case of GNSS data losses. In more detail, our novel ABIA system addresses all four cornerstones of GNSS integrity augmentation in mission- and safety-critical avionics applications: prediction (caution flags), avoidance (optimal flight path guidance), reaction (warning flags) and correction (recovery flight path guidance). Part 1 (Sabatini et al., 2012) presented the ABIA concept, architecture and key mathematical models used to describe GNSS integrity issues in aircraft applications. This second part addresses the ABIA caution and warning integrity flags criteria and presents the results of a simulation case study performed on the TORNADO Interdiction and Strike (IDS) aircraft.

Dual-Objective-Based Tornado Design Philosophy

AbstractTornadoes represent a unique natural hazard because of the very low probability of occurrence, short warning times (on the order of only a few minutes), and the intense and destructive forces imposed on engineered and nonengineered buildings. The very low-probability/very high-consequence nature of a tornado strike makes designing for survival and reducing damage under typical financial constraints a substantial challenge. On April 27, 2011, an enhanced Fujita (EF) 4 (EF4) tornado devastated an almost 10-km (5.9-mi) long, 0.8-km-wide (1/2-mi-wide) path, through the city of Tuscaloosa, Alabama, and continued on the ground for 130 km (80 mi). This paper presents the design concept that resulted following a week-long data reconnaissance deployment throughout the city of Tuscaloosa by the authors. The dual-objective philosophy proposed herein is intended to focus on both building damage and loss reduction in low-to-moderate tornado wind speeds and building occupant life safety in more damaging wind-sp...

Low-Level Winds in Tornadoes and Potential Catastrophic Tornado Impacts in Urban Areas

n an ambitious and provocative piece, Wurman et al. (2007, hereafter W07) explored the catastrophic potential of a violent tornado striking densely populated portions of Chicago, Illinois, and other major U.S. cities. This important paper was the first to predict the mortality of such an event, using tornadic wind fields, tornado path length and width, census data, housing types, degrees-of-damage (DOD) ratings, and probability-of-death (POD) estimates as predictors. In each of their simulations, Chicago suffered multiple thousands of deaths, with a worst-case estimate of 63,000. A recent comment and reply exchange between Brooks et al. (2008) and Wurman et al. (2008) dealt largely with the numerical accuracy of W07’s mortality projections in the context of previous urban tornadoes, and to a lesser extent, W07’s tornado model. I have modified this comment so as not to overlap with that debate. While I also question W07’s mortality estimates, I am most concerned with the underlying assumptions about the population. These assumptions, combined with several left-out factors, make the mortality estimates in W07 very difficult to believe, even after considering the additional reasoning in the Wurman et al. (2008) reply to the Brooks et al. (2008) comment. While modeling mortality at the city–tornado interface is, in itself, a very difficult undertaking, W07’s model could nevertheless be improved. The POD given a particular DOD should be used with other “death variables,” and a more sophisticated model of population dynamics. In simplified terms, the death toll for a given scenario in W07 is a function of 1) the population in low-rise, single family residential structures that face winds ≥76 m s–1, and 2) the population in highrise structures exposed to winds ≥102 m s–1. W07 use POD = 0.1 for all homes meeting criterion 1, and POD = 0.01 for all structures meeting criterion 2. In the case of their most lethal track (“HN”), they infer 630,000 criterion 1 residents, and thus, 0.1 × 630,000 = 63,000 deaths. The model assumes, however, that each censusregistered resident is at home when the tornado strikes. While it may be impossible to determine exactly where each of the 630,000 EF-4/5-affected residents in the HN scenario will be at the time of the tornado, one can be virtually certain that they will not all be at home. In fact, given the tendency for tornadoes to strike during the late afternoon and early evening—a time when many people are often in transit, coming from work, school, etc.—a W07-type tornado would likely affect many people not in their homes. Anyone familiar with Chicago knows that its “rush hour” often begins during midafternoon, and ends during the midevening; understanding the impacts of a rush-hour tornado therefore requires a thorough accounting of traffic densities and flows. Furthermore, a significant number of people would probably be outside, at least for a “prime time” tornado; this is Chicago after all. If one is modeling impacts, then one should account for the varying levels of impact among the mobilized population, not just the impacts to people in structures. To their credit, W07 did note that, “[t]he probability of dying in a tornado is likely sensitive to the time of day, the day of week, and the meteorological conditions, since these determine whether people are in their homes, driving, whether they are asleep or awake, and whether the tornado would be visible or surrounded by rain” (p. 40). It is unclear, however, why they otherwise ignored these important factors when estimating the impacts, especially since a study with a largely reproducible methodology already existed (and was cited in W07). Rae and Stefkovich (2000) used detailed economic, demographic, land use, and traffic data to model impacts from a major tornado in the Dallas–Fort Worth, Texas (DFW), area. While their tornado model merely superimposed tracks from the 3 May 1999 Oklahoma City tornadoes onto DFW, and was not as robust as the W07 tornado model, their treatment of the nontornado factors was superior to W07’s. Methodologies from “time geography,” which is concerned with daily population movements and has been employed by traffic modelers among others (e.g., Timmermans et al. 2002), could have further illuminated W07’s investigation. Incorporating more realistic variables into the model would, of course, require understanding critical wind thresholds for people who are stuck in traffic jams, driving in ordinary traffic, or are outDOI:10.1175/2008BAMS2670.1 I

Special Issue on Meteorological Disasters and Water Disasters in Urban Areas

Immediately after World War II, economic and human losses due to water disasters were enormous in Japan. In the years of 1947 and 1953, for example, economic loss reach 10% of personal income, and the number of lives lost in the 1959 Isewan Typhoon exceeded 5,000. The Japanese government then implemented successive 5-year flood control plans that dramatically reduced such disasters. Economic loss by flooding now is on the order of 0.2% of personal income, and fewer than 100 lives are lost per year. The situation has begun changing in the last decade, however, ostensibly due to global warming and local climatic change such as the heat island phenomenon. The most typical change is the increase in heavy precipitation. Meteorologists sometimes call 1997 the turning point in climate change. The year 1998 was one of extreme heavy rain in Japan, with downpours exceeding 100 mm/h occurring 10 times and those of 50 mm/h almost 440 times. The record for 50 mm/h was broken in 2004, when some 470 such downpours occurred. Another marked change has been the increase in the fluctuation of precipitation, suggesting that drought may follow floods as a typical pattern portending major water disasters in the future. Lifestyle changes are another factor inducing water disaster. Increased urban populations inherently induce concentrated land use, paving of land surfaces, hazardous living conditions, etc. Frequent urban flooding and high underground use in Japan increases the danger for inundations. Wind disasters are also increasing. In September 2006, a tornado in Nobeoka, Kyushu, killed 3 people. In November 2006, another tornado struck Saroma, Hokkaido, killing 9 workers when a construction company's meeting room was destroyed. Polluted material transported long distances by wind is a big problem in Asia. Smoke from forest fires and chemical pollutants increasingly endanger people outside of the countries of origin, spreading throughout the continent and to islands beyond. This issue reviews recent meteorological and hydrographic disasters in urban areas that threaten to become major problems in the 21st Century.