"Severe thunderstorms and tornadoes affect communities across the United States every year, causing fatalities, destroying property and crops, and disrupting businesses. State and local governments are typically the first to respond to the consequences of extreme weather events, but the federal government has responsibilities for forecasting and issuing warnings to citizens and communities lying in harm's way. When severe weather catastrophes overwhelm the resources of state and local governments, the Stafford Act authorizes the President to issue major disaster or emergency declarations, resulting in the distribution of a wide range of federal aid to those affected. Also, U.S. Department of Agriculture programs, such as federal crop insurance and emergency disaster loans, can help farmers recover financially from severe weather disasters even without a presidential disaster declaration. Many observers note that although the number of lives lost each year to natural hazards in the United States has decreased, the costs of major disasters continues to rise. According to the National Science and Technology Council: 'Due to changes in population demographics and more complex weather-sensitive infrastructure, Americans today are more vulnerable than ever to severe weather events caused by tornadoes, hurricanes, severe storms, heat waves, and winter weather.' For example, the tornado outbreak of February 5-6, 2008 (dubbed the Super Tuesday Tornado Outbreak), in several southern states (including Arkansas, Kentucky, Alabama, and Tennessee) caused approximately $850 million in insured losses and 57 fatalities. Insurance industry analysts indicate that tornadoes, severe thunderstorms, and related weather events (such as hailstorms, but not hurricanes or earthquakes) have caused nearly 57%, on average, of all insured catastrophe losses in the United States in any given year since 1953."
CRS Report for Congress, R40097