Pacific Island Network — Critical Issue Tropical Cyclones

When the warning sirens blare and the ity, and the visitor center at War in the Pacific wind picks up, what could we really be National Historical Park was damaged beyond in-store for? repair. Yet strong preparations and the public acumen during the storm prevented the loss Description: A is an orga- of life and allowed emergency responders and nized tropical weather system of strong thun- managers to focus on other pressing concerns. derstorms and well-defined circulation. Tropi- For Questions or Comments Contact: cal cyclones with sustained winds of less than [email protected] or 38 mph are called tropical depressions. Once [email protected] sustained wind speeds reach 39–73 mph they are referred to as tropical storms. Within the Super Typhoon Pongsona over the , How you can stay prepared: PACN, storms with sustained winds of 74 mph December 8, 2002. The term "super typhoons" refers We can all do our part to educate ourselves about or greater are termed hurricanes in Hawaii, typhoons with sustained 1-minute winds of at least the hazards presented by tropical cyclones, and 150 mph. typhoons in the Marianas and severe tropical plan and prepare for them. A wide variety of valu- cyclones in American Samoa. able, local awareness and preparedness informa- Nutrient cycles are changed because tropical tion is available through local meteorological and Tropical cyclones are products of (1) warm cyclones are significant drivers of erosion and public safety offices and you can stay informed by ocean waters (at least 800 F), (2) warm and deposition along coastal and inland waterways, tuning in to your local news (paper, radio, or TV). moist atmosphere, (3) a distance of at least 300 as well as causing extensive defoliation. Salt Regional advisory centers coordinate forecasts. miles from the equator for sufficient Coriolis stress, wind stress and flooding cause habitat For updates and more information: force, and (4) suitable near-surface and vertical alterations that particularly impact rare spe- http://www.nws.noaa.gov/om/hurricane/ wind shear conditions. However, many instanc- cies or those with confined geographic ranges. http://www.prh.noaa.gov/hnl/cphc/ es of favorable conditions do not develop into Furthermore, these changes often facilitate http://www.met.gov.fj/ tropical cyclones. the spread of alien species. Tropical cyclones http://www.jma.go.jp/en/typh/ also have a bearing on human populations and Occurrence in the Pacific Islands: In cultural resources as the storms threaten lives and the tropi- and alter physical structures such as cal cyclones of Saffir-Simpson scale 1 strength homes, monuments, or seawalls. or greater occur throughout the year. In Hawaii and American Samoa, they tend to occur during Management Consid- defined seasons (Hawaii: May – Oct.; American erations: Public safety is Samoa: Nov. - April). The western Pacific Ocean the primary management experiences far more tropical cyclones than the consideration before, rest of the Pacific Ocean (see map). Yet the en- during, and after tropi- tire network region is susceptible; the frequen- cal cyclones. The pass- cy is dependent upon the presence of suitable ing of Super Typhoon conditions for formation and wind conditions Pongsona in the Mari- that guide the path of an existing storm. ana Islands in 2002 provides an excellent Destructive Forces of Tropical Cy- example of the effec- clones: Tropical cyclones pose a variety of tiveness of education threats, which can extend hundreds of miles and preparedness. Despite from the storm’s center. Destructive forces in- sustained winds of over 150 clude strong winds, heavy rains, flooding from mph, and the , or center runoff or from , and tornadoes. of the storm, stationary over the Islands are especially impacted due to finite island of Guam for over two hours, land and coastal zone areas. The destruction of human fatalities were nil. Immediately after coral reefs leads to loss of biodiversity and robs the storm, hotel mattresses were strewn over Tropical Cyclone tracks in the Pacific basin during 2002–2003. Line color designates the maximum inten- the islands of natural protection from minor the beaches, the island's fuel depot was set sity reached during the life of the storm. Islands of the storms. ablaze by storm-generated static electric- Pacific Island Network identified by a red dot.

Pacific Island Network News 2006 Critical Issue http://science.nature.nps.gov/im/units/pacn/