Extreme weather is nothing new; there have always been floods, tornadoes, hurricanes, and other natural disasters. Only now, it seems such events are occurring more often, with greater intensity, and in some highly unusual places. Experts agree the primary reason is human activity that drives global warming and, ultimately, climate change. The result is rising land and water temperatures, rising sea levels, and marked differences in precipitation (less or more)­. Together, these effects create unprecedented hazard risks and social vulnerabilities for communities nationwide, deepening the need for greater mitigation measures. 

According to the U.S. Environmental Protection Agency (EPA