The Enhanced Fujita Tornado Scale
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Storm Wind Loads on Trees Thought by the Author to Provide the Best Means for Considering Fundamental Tree Health Care Issues Surrounding Tree Biomechanics
TreesTreesTrees &&& StormStormStorm WindWindWind LoadsLoadsLoads by Dr. Kim D. Coder Professor of Tree Biology & Health Care Warnell School of Forestry & Natural Resources, University of Georgia MAINE WASH. MN. VT. ND. NH. MICH. MONT. MASS. NY. 3 CT. RI. OR. WS. MICH. 2 NJ. ID. 1 SD. PA. WY. IOWA OH. DL. 5 NB. MD. IL. IN. W. NV. VA . VA . UT. CO. 6 KY. KS. MO. NC. CA. TN. SC. ARK. OK. 0 GA. AZ. AL. NM. 7 MS. TX. 8 4 LA. 9 FL. 10 Coder Storm Intensity Map of composite potential risks for tree damage. This publication is an educational product designed for helping tree professionals appreciate and understand basic aspects of tree mechanical loading during storms. This educational product is a synthesis and integration of weather data and educational concepts regarding how storms wind loads impact trees. This product is for awareness building and educational development. At the time it was finished, this publication contained information regarding storm wind loads on trees thought by the author to provide the best means for considering fundamental tree health care issues surrounding tree biomechanics. The University of Georgia, the Warnell School of Forestry & Natural Resources, and the author are not responsible for any errors, omissions, misinterpretations, or misapplications from this educational product. The author assumed professional users would have some basic tree structure and mechanics background. This product was not designed, nor is suited, for homeowner use. Always seek the advice and assistance of professional tree health providers for tree care and structural assessments. This educational product is only for noncommercial, nonprofit use and may not be copied or reproduced by any means, in any format, or in any media including electronic forms, without explicit written permission of the author. -
What Are We Doing with (Or To) the F-Scale?
5.6 What Are We Doing with (or to) the F-Scale? Daniel McCarthy, Joseph Schaefer and Roger Edwards NOAA/NWS Storm Prediction Center Norman, OK 1. Introduction Dr. T. Theodore Fujita developed the F- Scale, or Fujita Scale, in 1971 to provide a way to compare mesoscale windstorms by estimating the wind speed in hurricanes or tornadoes through an evaluation of the observed damage (Fujita 1971). Fujita grouped wind damage into six categories of increasing devastation (F0 through F5). Then for each damage class, he estimated the wind speed range capable of causing the damage. When deriving the scale, Fujita cunningly bridged the speeds between the Beaufort Scale (Huler 2005) used to estimate wind speeds through hurricane intensity and the Mach scale for near sonic speed winds. Fujita developed the following equation to estimate the wind speed associated with the damage produced by a tornado: Figure 1: Fujita's plot of how the F-Scale V = 14.1(F+2)3/2 connects with the Beaufort Scale and Mach number. From Fujita’s SMRP No. 91, 1971. where V is the speed in miles per hour, and F is the F-category of the damage. This Amazingly, the University of Oklahoma equation led to the graph devised by Fujita Doppler-On-Wheels measured up to 318 in Figure 1. mph flow some tens of meters above the ground in this tornado (Burgess et. al, 2002). Fujita and his staff used this scale to map out and analyze 148 tornadoes in the Super 2. Early Applications Tornado Outbreak of 3-4 April 1974. -
19.4 Updated Mobile Radar Climatology of Supercell
19.4 UPDATED MOBILE RADAR CLIMATOLOGY OF SUPERCELL TORNADO STRUCTURES AND DYNAMICS Curtis R. Alexander* and Joshua M. Wurman Center for Severe Weather Research, Boulder, Colorado 1. INTRODUCTION evolution of angular momentum and vorticity near the surface in many of the tornado cases is also High-resolution mobile radar observations of providing some insight into possible modes of supercell tornadoes have been collected by the scale contraction for tornadogenesis and failure. Doppler On Wheels (DOWs) platform between 1995 and present. The result of this ongoing effort 2. DATA is a large observational database spanning over 150 separate supercell tornadoes with a typical The DOWs have collected observations in and data resolution of O(50 m X 50 m X 50 m), near supercell tornadoes from 1995 through 2008 updates every O(60 s) and measurements within including the fields of Doppler velocity, received 20 m of the surface (Wurman et al. 1997; Wurman power, normalized coherent power, radar 1999, 2001). reflectivity, coherent reflectivity and spectral width (Wurman et al. 1997). Stemming from this database is a multi-tiered effort to characterize the structure and dynamics of A typical observation is a four-second quasi- the high wind speed environments in and near horizontal scan through a tornado vortex. To date supercell tornadoes. To this end, a suite of there have been over 10000 DOW observations of algorithms is applied to the radar tornado supercell tornadoes comprising over 150 individual observations for quality assurance along with tornadoes. detection, tracking and extraction of kinematic attributes. Data used for this study include DOW supercell tornado observations from 1995-2003 comprising The integration of observations across tornado about 5000 individual observations of 69 different cases in the database is providing an estimate of mesocyclone-associated tornadoes. -
ESSENTIALS of METEOROLOGY (7Th Ed.) GLOSSARY
ESSENTIALS OF METEOROLOGY (7th ed.) GLOSSARY Chapter 1 Aerosols Tiny suspended solid particles (dust, smoke, etc.) or liquid droplets that enter the atmosphere from either natural or human (anthropogenic) sources, such as the burning of fossil fuels. Sulfur-containing fossil fuels, such as coal, produce sulfate aerosols. Air density The ratio of the mass of a substance to the volume occupied by it. Air density is usually expressed as g/cm3 or kg/m3. Also See Density. Air pressure The pressure exerted by the mass of air above a given point, usually expressed in millibars (mb), inches of (atmospheric mercury (Hg) or in hectopascals (hPa). pressure) Atmosphere The envelope of gases that surround a planet and are held to it by the planet's gravitational attraction. The earth's atmosphere is mainly nitrogen and oxygen. Carbon dioxide (CO2) A colorless, odorless gas whose concentration is about 0.039 percent (390 ppm) in a volume of air near sea level. It is a selective absorber of infrared radiation and, consequently, it is important in the earth's atmospheric greenhouse effect. Solid CO2 is called dry ice. Climate The accumulation of daily and seasonal weather events over a long period of time. Front The transition zone between two distinct air masses. Hurricane A tropical cyclone having winds in excess of 64 knots (74 mi/hr). Ionosphere An electrified region of the upper atmosphere where fairly large concentrations of ions and free electrons exist. Lapse rate The rate at which an atmospheric variable (usually temperature) decreases with height. (See Environmental lapse rate.) Mesosphere The atmospheric layer between the stratosphere and the thermosphere. -
1 International Approaches to Tornado Damage and Intensity Classification International Association of Wind Engineers
International Approaches to Tornado Damage and Intensity Classification International Association of Wind Engineers (IAWE), International Tornado Working Group 2017 June 6, DRAFT FINAL REPORT 1. Introduction Tornadoes are one of the most destructive natural Hazards on Earth, with occurrences Having been observed on every continent except Antarctica. It is difficult to determine worldwide occurrences, or even the fatalities or losses due to tornadoes, because of a lack of systematic observations and widely varying approacHes. In many jurisdictions, there is not any tracking of losses from severe storms, let alone the details pertaining to tornado intensity. Table 1 provides a summary estimate of tornado occurrence by continent, with details, wHere they are available, for countries or regions Having more than a few observations per year. Because of the lack of systematic identification of tornadoes, the entries in the Table are a mix of verified tornadoes, reports of tornadoes and climatological estimates. Nevertheless, on average, there appear to be more than 1800 tornadoes per year, worldwide, with about 70% of these occurring in North America. It is estimated that Europe is the second most active continent, with more than 240 per year, and Asia third, with more than 130 tornadoes per year on average. Since these numbers are based on observations, there could be a significant number of un-reported tornadoes in regions with low population density (CHeng et al., 2013), not to mention the lack of systematic analysis and reporting, or the complexity of identifying tornadoes that may occur in tropical cyclones. Table 1 also provides information on the approximate annual fatalities, althougH these data are unavailable in many jurisdictions and could be unreliable. -
Fish & Wildlife Branch Research Permit Environmental Condition
Fish & Wildlife Branch Research Permit Environmental Condition Standards Fish and Wildlife Branch Technical Report No. 2013-21 December 2013 Fish & Wildlife Branch Scientific Research Permit Environmental Condition Standards First Edition 2013 PUBLISHED BY: Fish and Wildlife Branch Ministry of Environment 3211 Albert Street Regina, Saskatchewan S4S 5W6 SUGGESTED CITATION FOR THIS MANUAL: Saskatchewan Ministry of Environment. 2013. Fish & Wildlife Branch scientific research permit environmental condition standards. Fish and Wildlife Branch Technical Report No. 2013-21. 3211 Albert Street, Regina, Saskatchewan. 60 pp. ACKNOWLEDGEMENTS: Fish & Wildlife Branch scientific research permit environmental condition standards: The Research Permit Process Renewal working group (Karyn Scalise, Sue McAdam, Ben Sawa, Jeff Keith and Ed Beveridge) compiled the information found in this document to provide necessary information regarding species protocol environmental condition parameters. COVER PHOTO CREDITS: http://www.freepik.com/free-vector/weather-icons-vector- graphic_596650.htm CONTENT PHOTO CREDITS: as referenced CONTACT: [email protected] COPYRIGHT Brand and product names mentioned in this document are trademarks or registered trademarks of their respective holders. Use of brand names does not constitute an endorsement. Except as noted, all illustrations are copyright 2013, Ministry of Environment. ii Contents Introduction ....................................................................................................................... -
Indicative Hazard Profile for Strong Winds in South Africa Page 1 of 11
Research Article Indicative hazard profile for strong winds in South Africa Page 1 of 11 Indicative hazard profile for strong winds in AUTHORS: South Africa Andries C. Kruger1 Dechlan L. Pillay2 Mark van Staden2 While various extreme wind studies have been undertaken for South Africa for the purpose of, amongst others, developing strong wind statistics, disaster models for the built environment and estimations of AFFILIATIONS: tornado risk, a general analysis of the strong wind hazard in South Africa according to the requirements of 1South African Weather Service, the National Disaster Management Centre is needed. The purpose of the research was to develop a national Pretoria, South Africa profile of the wind hazard in the country for eventual input into a national indicative risk and vulnerability 2 Early Warnings and Capability profile. An analysis was undertaken with data from the South African Weather Service’s long-term weather Management Systems, National Disaster Management Centre, stations to quantify the wind hazard on a municipal scale, taking into account that there are more than 220 Centurion, South Africa municipalities in South Africa. South Africa is influenced by various strong wind mechanisms occurring at various spatial and temporal scales. This influence is reflected in the results of the analyses which indicated CORRESPONDENCE TO: that the wind hazard across South Africa is highly variable, spatially and seasonally. A general result was Andries Kruger that the strong wind hazard is highest from the southwestern Cape towards the central and eastern parts of the Northern Cape Province, and the southeastern parts of the coast as well as the eastern interior of the EMAIL: Andries.Kruger@weathersa. -
Estimating Enhanced Fujita Scale Levels Based on Forest Damage Severity
832 ESTIMATING ENHANCED FUJITA SCALE LEVELS BASED ON FOREST DAMAGE SEVERITY Christopher M. Godfrey∗ University of North Carolina at Asheville, Asheville, North Carolina Chris J. Peterson University of Georgia, Athens, Georgia 1. INTRODUCTION tion of how terrain-channeled low-level flow influences the mesoscale environment and tornadogenesis. Both Enhanced Fujita (EF) scale estimates following tor- Bluestein (2000) and Bosart et al. (2006) suggest that nadoes remain challenging in rural areas with few tra- further numerical simulations of the supercellular and ditional damage indicators. In some cases, traditional low-level environment are warranted. Indeed, numerous ground-based tornado damage surveys prove nearly im- authors use numerical simulations to study near-surface possible, such as in several 27 April 2011 long-track tornado dynamics (e.g., Dessens 1972; Fiedler 1994; tornadoes that passed through heavily forested and of- Fiedler and Rotunno 1986; Lewellen and Lewellen 2007; ten inaccessible terrain across the southern Appalachian Lewellen et al. 1997, 2000, 2008), but only recently has Mountains. One tornado, rated EF4, traveled 18 miles anyone attempted to incorporate very simple terrain vari- over the western portion of the Great Smoky Moun- ations into such models (e.g., D. Lewellen 2012, personal tains National Park (GSMNP) in eastern Tennessee. This communication). Thus, observational studies that char- tornado received its rating based on a single damage acterize the near-surface tornadic wind field in complex indicator—the tornado collapsed a metal truss tower topography remain vitally important. along an electrical transmission line (NWS Morristown 2011, personal communication). Although the upper Previous studies of tornado tracks through forests (e.g., Bech et al. -
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T839 BLOCK 3 Input 2 Beaufort wind scale Like the Richter scale for objective assessment of The scale was developed by Admiral Francis Beaufort of the earthquake severity, the Beaufort scale attempts to specify Royal Navy in about 1805 to provide an objective assessment the nature of a storm using a simple linear scale. While the of wind speed at sea, so that sailors could better judge what Richter scale is logarithmic, so a scale 5 earthquake is 10 sails to use or when to furl them when a storm approached. times more severe than a scale 4 earthquake, the Beaufort He therefore provided observations about the accompanying scale is linear in terms of wind speed (Table C1). state of the surface of the sea for each scale point. Table C1 Specification of the Beaufort scale with equivalents of the scale Beaufort Specification of Mean pressure (at Equivalent Limits of speed at force Beaufort scale for use on standard density) speed at 33 ft 33 ft (10 m) in the land, based on on a disc 1 ft2 (10 m) open observations made at land stations millibar lbf ft−2 knot mph knot mph m s−1 0 calm; smoke rises vertically 0 0 0 0 <1 <1 0–0.2 1 direction of wind shown by 0.01 0.01 2 2 1–3 1–3 0.3–1.5 smoke drift, but not by wind vanes 2 wind felt on face; leaves rustle; 0.04 0.08 5 5 4–6 4–7 1.6–3.6 ordinary vane moved by wind 3 leaves and small twigs in 0.13 0.28 9 10 7–10 8–12 3.4–5.4 constant motion; wind extends light flag 4 raises dust and loose paper; 0.32 0.67 13 15 11–16 13–18 5.5–7.9 small branches are moved 5 small trees in leaf begin to 0.62 1.31 -
The Historic Derecho of June 29, 2012
Service Assessment The Historic Derecho of June 29, 2012 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Weather Service Silver Spring, Maryland Cover Photograph: Visible satellite image at 5 p.m. Eastern Daylight Time (EDT) June 29, 2012, as the derecho moved across Ohio. National Lightning Data Network (NLDN) Cloud to ground (CG) lightning strikes for the 1-hour period, 4-5 p.m. EDT, are plotted in red. Surface observations are plotted in green. Smaller insets show radar reflectivity images of the derecho during the afternoon and evening. ii Service Assessment The Historic Derecho of June 29, 2012 January 2013 National Weather Service Laura K. Furgione Acting Assistant Administrator for Weather Services iii Preface On June 29, 2012, a derecho of historic proportions struck the Ohio Valley and Mid-Atlantic states. The derecho traveled for 700 miles, impacting 10 states and Washington, D.C. The hardest hit states were Ohio, West Virginia, Virginia, and Maryland, as well as Washington, D.C. The winds generated by this system were intense, with several measured gusts exceeding 80 mph. Unfortunately, 13 people were killed by the extreme winds, mainly by falling trees. An estimated 4 million customers lost power for up to a week. The region impacted by the derecho was also in the midst of a heat wave. The heat, coupled with the loss of power, led to a life-threatening situation. Heat claimed 34 lives in areas without power following the derecho. Due to the significance of this event, the National Oceanic and Atmospheric Administration’s National Weather Service formed a Service Assessment Team to evaluate the National Weather Service’s performance before and during the event. -
On the Implementation of the Enhanced Fujita Scale in the USA
Atmospheric Research 93 (2009) 554–563 Contents lists available at ScienceDirect Atmospheric Research journal homepage: www.elsevier.com/locate/atmos On the implementation of the enhanced Fujita scale in the USA Charles A. Doswell III a,⁎, Harold E. Brooks b, Nikolai Dotzek c,d a Cooperative Institute for Mesoscale Meteorological Studies, National Weather Center, 120 David L. Boren Blvd., Norman, OK 73072, USA b NOAA/National Severe Storms Laboratory, National Weather Center, 120 David L. Boren Blvd., Norman, OK 73072, USA c Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, 82234 Wessling, Germany d European Severe Storms Laboratory (ESSL), Münchner Str. 20, 82234 Wessling, Germany article info abstract Article history: The history of tornado intensity rating in the United States of America (USA), pioneered by Received 1 December 2007 T. Fujita, is reviewed, showing that non-meteorological changes in the climatology of the Received in revised form 5 November 2008 tornado intensity ratings are likely, raising questions about the temporal (and spatial) Accepted 14 November 2008 consistency of the ratings. Although the Fujita scale (F-scale) originally was formulated as a peak wind speed scale for tornadoes, it necessarily has been implemented using damage to Keywords: estimate the wind speed. Complexities of the damage-wind speed relationship are discussed. Tornado Recently, the Fujita scale has been replaced in the USA as the official system for rating tornado F-scale intensity by the so-called Enhanced Fujita scale (EF-scale). Several features of the new rating EF-scale Intensity distribution system are reviewed and discussed in the context of a proposed set of desirable features of a tornado intensity rating system. -
T. Theodore Fujita Professor of Meteorology the University of Chicago
*1> Of TORNADOES c3nd HIGH WINDS I / For Engineering Appl ications I \ BY T. THEODORE F U J I T A A ;I , / I I I ), 'I \, W O R K B O O K of TOR NAD O ES AND HI G H WINDS for Engineering Applications by T. Theodore Fujita Professor of Meteorology The University of Chicago September 1978 This workbook was prepared by T. Theodore Fujita under Argonne National Laboratory Contract No. 31-109-38-4500 for use in the Department of Energy, Division of Operational and Environmental Safety, Workshops on .Tornadoes and High Winds. (July and September 1978 at Argonne National Laboratory) 0 Design-basis tornado (DBT-77) in Chapter 6 was finalized in the summer of 1977 under ANL Contract No. 31-109-38-3731. o Basic concept of DBT-78 leading to -the computation of new DAPPLE values was developed under NRC Contract No. AT(49-24)-0239. PREFACE At the request of Mr. W. J. McCool, DOE, two workshops on tornadoes and high winds were organized and a workbook prepared for DOE personnel. The emphasis in the workshops, held at Argonne National Laboratory, Illinois in July and September, 1978 is on the understanding of meteorological phenomena related to severe local storms in general and the tornado in particular. The workshops cover a range of topics dealing with terminology, meteo- rology aspects, photogrammetric analyses, aerial surveys, statistical data base, hazard probabilities and analytical models of tornadoes that incorporate suction vortices. This workbook, prepared by the principal lecturer, outlines the current state-of-knowledge of the above subjects.