Hurricane Preparedness 2

Dave Nussbaum & Chris Stevens
dnussbaum@wbrz.com

High Winds

Each hurricane will contain a very large area of high winds.  These winds can obviously be destructive, and plenty of damage is typically seen.  To become a tropical system must obtain winds of less than 39 mph to become a tropical depression.  These winds usually do not to too much damage when it moves onshore

Once the winds are 39 mph or greater, it become a tropical storm.  Winds can be as high as 73 mph, and much more damage is then seen on an land falling tropical storm.  Since the winds are sustained between 39-73 mph, you will see more trees down, roofs damaged, and signs blown down. 

When the winds become 74 mph or greater then you have a hurricane.  A hurricane is rated using the Saffir Simpson Scale to show its strength.  Here is a breakdown of what kind of damage you can see from the winds:

Category 1: Winds 74-95 mph, Minimal Damage

• Mobile homes tipped over
• Uproot and snap trees
• Roof shingles and tiles get blown off

Category 2: Winds 96-110 mph, Moderate Damage

• Mobile Homes are badly damaged
• Manufactured homes suffer structural damage
• Small boats in unprotected anchorages may break away

Category 3: Winds 111-130 mph, Extensive Damage

• Known as a Major Hurricane
• Destroys mobile homes
• Peels off some roofs
• Manufactured and well built homes sustain heavy damage
• Significant flooding along the coast, minor flooding inland

Category 4: 131-155 mph, Extreme Damage

• Complete roof and structural damage on most houses
• Manufactures homes are usually leveled
• Major beach erosion and more significant inland flooding likely

Category 5: 156+ mph, Catastrophic Damage

• Very few structure survive, and only if located 3 to 5 miles inland
• Many coastal structures flattened or washed away by the storm surge

Storm Surge

The Storm Surge and high waves typically are the most destructive part of a hurricane.   The storm surge is defined as the abnormal rise in sea level accompanying a hurricane or other intense storm, and whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the storm. 

For example, Hurricane Katrina had about a 28 foot storm surge along the Mississippi coast.  That means that the water was 28 feet higher than it would be on a calm and sunny day.