Is Your Community at Risk of Storm Surge Impacts?
Hollywood's two hurricane evacuation zones encompass all areas of the City east of Federal Highway, including Hollywood Lakes and Hollywood beach. Evacuation zones are established primarily because of the risk of storm surge in these areas. However, areas outside of the established hurricane evacuation zones may also experience storm surge impacts during a hurricane.
Wondering if your community may be impacted by storm surge during a hurricane? Visit the National Hurricane Center's Interactive Storm Surge Risk Map website to determine whether your community is at risk
What Is Storm Surge?
Storm surge is the elevation of a body of water generated by a storm, over and above the predicted astronomical tides. The elevation is caused primarily by a hurricane's strong winds, though a storm's central pressure, astronomical tides and the offshore shelf (water depth) also contribute to storm surge severity. Storm surge is not a large wave, which generally recedes quickly after impact. Storm surge is also not a tsunami, which is caused by an underwater event such as a volcanic eruption or earthquake. Storm surge impacts can last hours or even days.
Though hurricanes are categorized based on their maximum sustained wind speed (known as the Saffir-Simpson scale), storm surge is considered to be the deadliest hazard associated with a tropical cyclone. A 2014 report by Dr. Ed Rappaport, Deputy Deputy of the National Hurricane Center (NHC), stated that water is the No. 1 killer during a hurricane or tropical storm that strikes the U.S. – comprising nearly 90 percent of all tropical cyclone deaths – mostly by drowning in either storm surge, rainfall flooding or high surf. Of those fatalities, nearly half were caused by storm surge, according to the study.
Location plays a role in how significant storm surge is during a hurricane. Landmasses adjacent to bodies of water that are relatively shallow such as the Gulf of Mexico tend to experience greater storm surge impacts. For example, a Category 4 storm hitting the Louisiana coastline, which has a very wide and shallow continental shelf, may produce a 20-foot storm surge, while the same hurricane in a location like Hollywood where the continental shelf drops off very quickly might see an 8 or 9-foot surge. The Fort Myers area reportedly experienced up to an 18-foot storm surge during Hurricane Ian. However, Florida's Atlantic Coast can experience catastrophic storm surge impacts. A good example is Hurricane Andrew, a Category 5 hurricane that ravaged Miami-Dade County's southern coast with a reported 17-foot surge in August 1992.
According to the NHC's Storm Surge Risk Map tool and the National Weather Service in Miami, a direct Category 5 hurricane strike on Hollywood's coast could result in a 9 to 12-foot storm surge:
- Impacts all of the City just past Federal Highway. The water level in most of that area, particularly Hollywood Lakes, could be greater than 3 feet above ground. Some areas such as the Anne Kolb Nature Center and neighborhoods just north and south of Hollywood Boulevard east of 13th Avenue could experience water levels greater than six feet above ground.
- The surge could reach parts of Dixie Highway in southeast Hollywood and impact homes along canals and lakes near Interstate 95. Examples of areas that could experience storm surge impacts of less than 3 feet include Rotary Park and neighborhoods along North 28th Avenue between Taft and Sheridan Streets.
The location of the hurricane's eye also factors into where the storm surge impact is greatest. For example, Hollywood would likely experience a greater storm surge impact from a hurricane whose eye made landfall just south of the City limit than directly over the City. The winds circulating counterclockwise around the eye of the hurricane are the storm's fiercest. So if you were to have a hurricane moving west off the Atlantic Ocean over the Miami-Dade-Broward County line and the storm's northern eyewall makes landfall just south of Hollywood Boulevard, the storm's winds at that point would push water onto Hollywood's barrier island and Hollywood Lakes while winds circulating around the storm's western and southern eyewall would move water south and east, respectively. Areas north of the eyewall and within the storm's hurricane force wind field also would experience significant storm surge impacts.
Storm Surge Modeling and Hurricane Evacuation Zones in Hollywood
The NHC uses a computerized numerical model designed by the NWS known as the Sea, Lake and Overland Surges from Hurricanes (SLOSH) to estimate storm surge heights from historical, hypothetical or predicted hurricanes by taking into account the atmospheric pressure, size, forward speed, and track data. These parameters are used to create a model of the wind field that drives the storm surge. The NHC provides these estimates and models with its hurricane and tropical storm advisories. Hollywood's two hurricane evacuation zones - Zone A, which includes the barrier island and Zone B, which runs from the Intracoastal Waterway to Federal Highway - were established by Broward County using SLOSH and FEMA flood mapping software.