The Saffir-Simpson Hurricane Scale is a scale classifying most Western Hemisphere tropical cyclones that exceed the intensities of "tropical depressions" and "tropical storms", and thereby become hurricanes
The Saffir-Simpson Hurricane Scale is used only to describe hurricanes forming in the Atlantic Ocean and northern Pacific Ocean east of the International Date Line. Other areas label their tropical cyclones as "cyclones" and "typhoons", and use their own classification scales.
Effects include impact of: waves; storm surge; wind; rainfall/ flooding. Greatly influenced by vulnerability: · physical factors: intensity; distance from sea; length of time over area, etc.; · human factors: economic development; warning! evacuation; procedures etc.;· direct and indirect effects (landslides, etc.);· how to measure impact.
On land, strong winds can damage or destroy vehicles, buildings, bridges, and other outside objects, turning loose debris into deadly flying projectiles. The storm surge, or the increase in sea level due to the cyclone, is typically the worst effect from landfalling tropical cyclones, historically resulting in 90% of tropical cyclone deaths
Since 1953, Atlantic tropical storms have been named from lists originated by the National Hurricane Centre. They are now maintained and updated by an international committee of the World Meteorological Organization. The original name lists featured only women's names. In 1979, men's names were introduced and they alternate with the women's names. Six lists are used in rotation. Thus, the 2006 list will be used again in 2012.
PREDICTION IS BASED ON PAST EVIDENCE AND IS EXPRESSED AS PROBABILITIES .
NOAA is predicting a very high likelihood (85% chance) of an above-normal 2007 Atlantic hurricane season, a 10% chance of a near-normal season, and only a 5% chance of a below-normal season, according to a consensus of scientists at the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Centre, National Hurricane Centre, Hurricane Research Division, and Hydro meteorological Prediction Centre.
17 named tropical storms ; an average season has 9.6.
9 hurricanes compared to the average of 5.9.
5 major hurricanes with winds exceeding 110 mph; average is 2.3.
Though these statistical predictions cannot portend when any of the storms will form or where they will go, Klotzbach, Gray and colleagues calculate an 81 percent chance that at least one major hurricane will hit the U.S. coast in 2006.
How the 2006 forecast compares: 20052006Avg.Tropical Storms 26179.6Hurricanes1395.9Major Hurricanes752.3
In the 1960s and 1970s, the United States government attempted to weaken hurricanes through Project Stormfury by seeding selected storms with silver iodide. It was thought that the seeding would cause supercooled water in the outer rainbands to freeze, causing the inner eyewall to collapse and thus reducing the winds.