LITMIR.BIZ

Figure 1‐2 Hurricane Sandy struck the northeast and destroyed this roller coaster on the boardwalk in Seaside Heights, NJ. Liz Roll/FEMA.Adapted from http://www.nhc.noaa.gov/aboutsshws.php

      1.2.2 Atmospheric Hazards

An atmospheric hazard is a hazard agent that is produced in or by the earth’s atmosphere. A hurricane is one type of atmospheric hazard (Figure 1‐2). Hurricanes begin as tropical depressions in the Atlantic Ocean and form as low‐pressure systems due to the warm water that fuels them. When wind speeds top 74 mph, such

tropical depressions become known hurricanes. In the Indian Ocean, these tempests are known as cyclones, and in the Pacific Ocean they are labeled typhoons. The eye or center of these storms is somewhat calm, but it is surrounded by circling cloud bands that produce rain in large amounts. Some hurricanes may have winds in excess of 100 or even 200 mph, and they may produce a storm surge that could reach up to 24 feet. The strength of a hurricane is described under the Saffir–Simpson scale. The Saffir–Simpson scale is a descriptive tool to explain the magnitude of a hurricane in terms of wind and storm surge. It includes five categories. Category 1 is the weakest, while Category 5 is the strongest (see Table 1‐2).

      This scale also estimates potential property damage. On the lower end of the scale, category 1 and 2 storms are smaller, but could nevertheless be dangerous and still require preparatory measures. Hurricanes reaching Category 3 and higher are considered major storm systems because of their potential for significant loss of life and damage. In the western North Pacific, the term “super typhoon” is used for tropical cyclones with sustained winds exceeding 150 mph.

In the Northern Hemisphere, hurricanes rotate in a counterclockwise direction and travel in a west–northwesterly direction. They frequently hit Atlantic states and those along the Gulf Coast. Florida is one of many states that frequently experiences hurricanes. For instance, Hurricane Andrew made landfall on August 24, 1992, and its strong winds devastated the Miami‐Dade area. This hurricane produced dozens of deaths and left thousands of people without power and shelter. Weak building codes and poor enforcement resulted in major structural collapses and a debris management nightmare. Hurricane Andrew’s impact on Florida was surpassed by the combined four hurricanes and one tropical storm that hit Florida in 2004. This was one of the worst hurricane seasons on record, but such storms have become even more problematic over the past few decades.

Table 1‐2 Saffir–Simpson Hurricane Scale.

      Source: Adapted from Saffir‐Simpson Hurricane Wind Scale, NOAA. http://www.nhc.noaa.gov/aboutsshws.php.