NEQ Spotlight: Saffir-Simpson

Throughout the next several months you'll hear the terms tropical depression, tropical storm, hurricane, major hurricane... and while we know the term 'major hurricane' refers to something we should probably be scared of, for those less versed in the Saffir-Simpson hurricane scale, that term might have a different meaning. Well alas, today's NEQ Spotlight takes a closer look at the Saffir-Simpson Hurricane Wind Scale (formerly accounting for storm surge, hence the addition of the term wind), which separates hurricanes into five categories distinguished by the intensities of their sustained winds.

Developed in 1971 by civil engineer Herbert Saffir and meteorologist Bob Simpson, adopted by the National Hurricane Center (NHC) in 1973 and updated in 2010, the Saffir-Simpson Scale is now based strictly on wind speed and is meant to show on a scale from 1 (the weakest) to 5 (the most intense) the expected damage to structures as a result of a landfalling hurricane. The scale does not take into account storm surge, rainfall, barometric pressure or other elements of a tropical cyclone.

Within the scope of the Saffir-Simpson Scale there is a subset of storms defined as major for those classified as category 3 or higher. A major hurricane is capable or producing extensive to catastrophic damage.

The graphic above defines the categories in the Scale, their associated wind speeds and the potential damage at landfall. With all eyes on a strengthening Alex this week, this scale will definitely be referred to and should be something you become familiar with – now and throughout hurricane season.

Thanks Saffir-Simpson for your contribution to meteorology and involuntarily offering yourself up to today's NEQ Spotlight!

Reference 1: See earlier blog post: New Hurricane Wind Scale for 2010 Season
Reference 2: Check out this transcript from a 1991 interview with Dr. Simpson

New Hurricane Wind Scale for 2010 Season

Beginning the 2010 hurricane season, which runs from June 1 – November 30 for the Atlantic Basin (i.e. Atlantic Ocean, Caribbean Sea, Gulf of Mexico), the National Hurricane Center will be categorizing storms using a new version of the Saffir-Simpson scale.

The new Saffir-Simpson Hurricane Wind Scale will keep the same wind speed ranges as the original Saffir-Simpson Scale for each of the five hurricane categories, but no longer ties specific storm surge and flooding effects to each category.

The modification to the previous scale comes as realizations were made that storm surge values and associated flooding are dependent on a combination of the storm’s intensity, size, motion and barometric pressure, as well as the depth of the near-shore waters and local topographical features. The National Hurricane Center says storm surge forecasts will continue to be included in hurricane advisories.

If you live in a hurricane prone area, below are the categories you should become familiar with:

Category One (Sustained winds 74-95 mph) – Severe winds will produce some damage and minor flooding is possible. Example: Humberto, 2007

Category Two (Sustained winds 96-110 mph) – Dangerous winds and moderate flooding will cause extensive damage. Example: Dolly, 2008

Category Three (Sustained winds 111-130 mph) – Extremely dangerous winds and significant flooding will cause devastating damage to occur. Example: Fran, 1996

Category Four (Sustained winds 131-155 mph) – As a result of destructive winds and flooding catastrophic damage will occur with very few structures remaining. Example: Charley, 2004

Category Five (Sustained winds greater than 155 mph) – Unfathomable winds speeds and flooding will cause mass catastrophic damage to occur and structures will be left in ruins. Example: Katrina, 2005

Stay tuned! In early April the official 2010 Atlantic Hurricane Season forecast will be released. You can bet The Northeast Quadrant will be on top of it!