1) Eva Lipiec authored (13 December 2021) this CRS Insight report: 'Tornadoes: Background and Forecasting'.
Insight reports have embedded URLs that may not be displayed on a PDF. If not, access the online version to see them. I have pasted the entire report below.
Download CRS_Insight_Tornadoes_Background_Forecasting_13Dec2021
Background
Severe thunderstorms and tornadoes affect communities across the United States every year, causing fatalities, destroying property and crops, and disrupting businesses. Tornadoes are narrow, violently rotating columns of air that extend from the base of a thunderstorm to the ground, sometimes producing winds that exceed 300 miles per hour. Tornadoes have been reported on all continents except Antarctica; however, they occur most commonly in North America and particularly in the United States, which reports approximately 1,200 tornadoes per year. Tornadoes occur across the United States but form most commonly in three regions, shifting seasonally: (1) southern Plains (e.g., Texas, Oklahoma, Kansas), (2) Gulf Coast, and (3) northern Plains and upper Midwest (e.g., North and South Dakota, Nebraska, Iowa, Minnesota). Depending on geographic location, tornadoes occur mostly during spring and summer (Figure 1) and usually during the late afternoon or early evening. However, tornadoes can occur at any time. For example, a deadly storm system with several reported tornadoes, including a “significant long track tornado,” touched ground overnight in Arkansas, Illinois, Kentucky, Missouri, Mississippi, and Tennessee between December 10 and 11, 2021. Preliminary estimates report that peak winds of the long-track tornado reached between 158 and 206 miles per hour. Aspects of the event were rare, such as its timing, potential track length, and geographic location.
Classification
Experts estimate the strength or wind speed of a tornado by examining the damage it caused rather than by measuring actual wind speeds during an event. The Fujita, or F-scale, estimation method, developed in 1971, was used for over three decades, but its limitations prompted the development and adoption of a new scale in 2007, called the enhanced F-scale, or EF-scale (Table 1). The EF-scale is intended to be a more robust and precise method of assessing a tornado’s strength, and it uses 28 different types of damage indicators, such as building type, structures, and trees.
Forecasting, Detection, and Communication
Exactly how and why tornadoes form is not completely understood. Tornado formation is believed to be dictated mainly by storm-scale conditions in and around rotating thunderstorms with well-defined circulation. The National Oceanic and Atmospheric Administration’s (NOAA’s) National Weather Service (NWS), at the discretion of the Secretary of Commerce, has statutory authority for weather forecasting and for issuing storm warnings (15 U.S.C. §313). NWS provides weather, water, and climate forecasts and warnings for the United States, its territories, adjacent waters, and ocean areas. In addition, several NOAA programs, including the National Severe Storm Laboratory, focus on research to improve observations, modeling, and instrument development, among other activities.
Forecasting and Detection
Severe thunderstorm and tornado forecasts are made by the NWS Storm Prediction Center (SPC) and by local weather forecast offices (WFOs). SPC forecasters use weather observations, numerical weather prediction models, and ensemble forecasting (running several models at one time) to determine if atmospheric conditions, temperature, and wind flow patterns may lead to the formation of severe weather. SPC issues three-day forecasts (convective outlooks) on a daily basis and mesoscale discussions of severe thunderstorm potential for the next six hours, with an emphasis on the next one to three hours, as warranted.
If conditions favorable for either multiple tornadoes or a single intense tornado continue to develop, SPC issues a tornado watch that typically lasts six to eight hours. Such watches alert the public, emergency managers, storm spotters, broadcast media, and local WFOs that conditions have become favorable for the development of tornadoes. SPC aims to issue watches at least two hours before the first tornado event.
Forecasters and storm spotters recognize certain storm features from visual cues, such as the rear-flank downdraft, and particular patterns in Doppler radar images, such as the tornadic vortex signature (a region of intense concentrated rotation). WFOs issue tornado warnings when a tornado has been sighted or indicated by weather radar. The warning contains specific language about areas at risk, time frames, specific hazards, recommended safety precautions for those at risk, and the WFO issuing the warning.
Communication
Several methods exist to communicate warnings to the public, including outdoor warning sirens, local television and radio stations, cable television systems, cell phone applications, and NOAA Weather Radio All Hazards (NWR). NWS maintains and operates NWR, a nationwide network of radio stations broadcasting continuous weather information directly from the nearest WFO 24 hours a day, 7 days a week. NWR works with the Emergency Alert System, an automated system that allows NWS warnings to be disseminated over broadcasters, satellite digital audio services, direct broadcast satellite providers, cable television systems, and wireless cable systems.
Considerations
It is not clear whether the average number of tornadoes each year has changed over time, due to reporting issues, and if climate change has, or may, impact tornado frequency or intensity overall or in certain circumstances (see here for more about the differences between weather and climate). Congress may consider whether and how federal agencies should continue research into potential connections between climate change and tornado activity and whether there are ways to mitigate any climate change impacts. Additional considerations for Congress may include how social, behavioral, and demographic factors play a role in tornado-related fatalities and federal responsibilities in preventing and responding to damages from windstorms, such as tornadoes.
2) Lauren R. Stienstra coordinated (updated 17 December 2021) this CRS Insight report: 'Southeastern Tornado Outbreak: Brief Overview of FEMA Programs and Resources'.
Download CRS_Insight_Report_SE_Tornado_Outbreak_FEMA_Pgms_Resources_17Dec2021
Insight reports have embedded URLs that may not be displayed on a PDF. If not, access the online version to see them. I have pasted the entire report below.
Introduction
A late-season tornado outbreak produced significant damage and numerous fatalities across portions of the southeastern United States and Ohio Valley from the evening of December 10 to the early morning of December 11, 2021. This Insight briefly overviews emergency and major disaster declarations and federal assistance programs relevant to those affected by the storm. It also provides selected Congressional Research Service (CRS) reports on federal emergency management policy.
President Joseph R. Biden, Jr. signed an emergency declaration for Kentucky (December 11) under the Robert T. Stafford Disaster Relief and Emergency Assistance Act (P.L. 93-288, as amended; 42 U.S.C. §§5121 et seq.), to support state and local efforts to save lives, protect property, and avert the incident from becoming a major disaster. Under the declaration, Public Assistance (PA) for emergency protective measures is available for 16 counties. Subsequently, President Biden declared a major disaster forKentucky (December 12), making available a broader range of federal assistance programs to state, local, and territorial governments, private nonprofit organizations, and individuals through the Federal Emergency Management Agency (FEMA) and other federal agencies, including PA for emergency work (e.g., debris removal and emergency protective measures) and IndividualAssistance (IA) for eight counties. The Hazard Mitigation Grant Program (HMGP) is available throughout the entire commonwealth.
On December 13, 2021, President Biden approved emergency declarations authorizing PAemergency protective measures for nine counties in Tennessee and 13 counties in Illinois.
Additional declarations for other states (or additional forms of assistance for existing declarations) may be forthcoming if the President determines that federal assistance is necessary to support state and local recovery. This information will be published in FEMA’s declaration database.
FEMA’s website provides additional information on federal response efforts related to the tornado outbreak.
FEMA Emergency and Major Disaster Assistance
FEMA provides three major categories of assistance, some of which may be available pursuant to an emergency declaration and/or a major disaster declaration:
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Public Assistance (PA) provides grants and direct assistance to state, tribal, territorial, and local governments, and certain private nonprofit organizations, for emergency work (can be authorized pursuant to either an emergency or major disaster declaration), and permanent work (can only be authorized pursuant to a major disaster declaration).
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Individual Assistance (IA) provides financial and/or direct assistance to affected individuals and households, and can take the form of housing assistance and assistance for other needs (can be authorized pursuant to either an emergency or major disaster declaration), as well as crisis counseling, case management services, legal services, and disaster unemployment assistance (can only be authorized pursuant to a major disaster dec laration).
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Hazard Mitigation Assistance (HMA) funds mitigation and resiliency projects and programs, typically across the entire state or territory. States which receive a major disaster declaration are awarded Hazard Mitigation Grant Program (HMGP) funding.
The forms of assistance authorized by a declaration may vary by the designated areas, per the declaration (subject to amendment). The President can also amend emergency and major disaster declarations to decrease the cost-share requirements for PA.
Federal Funding for Disaster Response and Recovery
Typically, Congress also expresses interest in funding following a disaster declaration. FEMA’s Disaster Relief Fund (DRF) is the primary source of federal government resources for response and recovery activities. It is often used as an indicator of the overall availability of federal resources for response and recovery.
As a result of historically high levels of annual and supplemental appropriations provided in recent fiscal years associated with Coronavirus Disease 2019 (COVID-19) response, the balance in the DRF stood at more than $40 billion in unobligated funds for major disasters before the tornadoes struck, more than a third of which was from the FY2022 continuing resolution. These resources are available to support the elements of the federal response and recovery effort authorized under the StaffordAct. DRF funds do not expire at the end of the fiscal year, and are to remain available until expended.
Additional Recovery Resources
FEMA Programs and Resources:
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Public Assistance Program Overview
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Individual Assistance Program Overview
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Hazard Mitigation Grant Program Overview
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FEMA Blog
CRS Resources
Tornado Resources
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CRS Report R46438, Natural Disasters and Hazards: CRS Experts
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CRS Report R44977, Preliminary Damage Assessments for Major Disasters: Overview, Analysis, and Policy Observations
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CRS Report R44941, Disaster Debris Management: Requirements, Challenges, and Federal Agency Roles
Federal Disaster Assistance—Process and Programs
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CRS Report WMR10001, CRS Guide to Federal Emergency Management
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CRS Report RL31734, Federal Disaster Assistance Response and Recovery Programs: Brief Summaries
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CRS Report R41981, Congressional Primer on Responding to and Recovering from
Major Disasters and Emergencies, by Bruce R. Lindsay and Elizabeth M. Webster.
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CRS Report R46749, FEMA’s Public Assistance Program: A Primer and Considerations for Congress, by Erica A. Lee
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CRS Report R46014, FEMA Individual Assistance Programs: An Overview
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CRS Insight IN11187, Federal Emergency Management Agency (FEMA) Hazard Mitigation Assistance
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CRS Report R45238, FEMA and SBA Disaster Assistance for Individuals and Households: Application Processes, Determinations, and Appeals
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CRS Report R43537, FEMA’s Disaster Relief Fund: Overview and Selected Issues
You can search for these CRS reports here.
Enjoy!
"Inside every silver lining there's a dark cloud." - George Carlin (as Al Sleet, the Hippy Dippy Weatherman)
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