Hurricanes

Hurricanes are storms that form over tropical or subtropical water and have the potential to produce devastating winds and flooding from storm surge and extreme rainfall. Both flooding and high winds are dangerous safety risks and cause significant property damage.


Aaron Baker

May 7, 2021 • Updated Mar 17, 2022 • 5 min read
Natural Hazards

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Overview#

Hurricanes are low-pressure storm systems that form over tropical or subtropical water with surface winds that move in a continuous circular motion. Major hurricanes can be devastating storms that can produce strong winds, flooding from storm surge and extreme rainfall, and tornadoes. Hurricanes form over warm water (80℉ or warmer), at least 200 miles north of the equator, and with an atmosphere that contains moist air and cooler temperatures at higher altitudes.

The Atlantic hurricane season is from June 1st to November 30th and in the eastern Pacific, it runs from May 15th to November 30th. Over the past 140 years, the Atlantic basin typically produces 12 named storms per year of which six develop into hurricanes and three into major hurricanes. The eastern Pacific averages about 15 named storms per year of which about eight develop into hurricanes and four into major hurricanes. Most of the storms and hurricanes in the eastern Pacific move west away from the coast and do not make landfall in North America.

All states along the Gulf of Mexico and Atlantic coast are in the potential path of hurricanes and tropical storms. About 40% of all northern Atlantic hurricanes strike Florida. Although there are no documented cases of a hurricane making landfall in California, flooding from storm surge and extreme rainfall occur from offshore hurricanes and tropical storms. Hurricanes are also rare in Hawaii as a result of a combination of water temperature and atmospheric conditions. Only five hurricanes have caused serious damage in the Hawaiian islands in the last 70 years.

The pattern of hurricane intensity and possibly frequency in both the Atlantic and Pacific is changing. Recent research suggests that there has been an increase in intense hurricane activity over the past 40 years due to measurable changes in the environment--a trend that is predicted to continue if ocean and atmospheric temperatures continue to increase.

Hurricanes are a type of tropical cyclone and are classified into five categories by wind speed that can cause significant damage to well-constructed framed homes and trees.

Hurricane Categories, Wind Speeds, and Potential Damage from Wind#

CATEGORYWIND SPEEDDAMAGE
174-95 mphSome damage could occur to the roof, shingles, vinyl siding, and gutters. Large branches of trees will snap and trees with shallow roots may be toppled.
296-110 mphExtensive damage to roofs and siding could occur. Many shallowly rooted trees will be snapped or uprooted.
3111-129 mphMajor damage or removal of roof decking and gable ends will occur. Many trees will be snapped or uprooted.
4130-156 mphSevere damage with loss of roof and/or some exterior walls can occur. Most trees will be snapped or uprooted.
5157+ mphA majority of homes will be destroyed with total roof failure and wall collapse. Most trees will be snapped or uprooted.

Storm surge and extreme rainfall are important components of hurricanes. Storm surge is water that is pushed towards shore by hurricane winds creating an abnormal rise in sea level. Storm surge combined with a normal high tide is called a storm tide and can be over 15 feet above a normal high tide and flood as much as 30 miles inland from the coast. Extreme rainfall results from warm moist air that rises in a hurricane and typically produces 6-12 inches of rain.

Nearly all hurricanes that pass over land produce at least one tornado between 50 and 300 miles from the eye of the storm. While most tornadoes associated with hurricanes are short-lived and weaker than those that occur in the great plains, they can produce dangerous and destructive winds up to 300 mph.

Your Home and Hurricanes#

Health and Safety#

Flooding from storm surge and extreme rainfall is the most important safety concern. Between 1963 and 2012 almost 90% of all fatalities with a known cause of death associated with hurricanes can be attributed to water hazards that include flooding from storm surge and extreme rainfall, wave and rip currents, and offshore marine incidents. Flooding from storm surge and extreme rainfall accounts for 75% of all fatalities.

The National Oceanic and Atmospheric Administration (NOAA) issues public advisories every three hours whenever there is a hurricane or other category of tropical cyclone in the Atlantic or eastern Pacific. NOAA recommends that the best way to stay safe is to run from water and hide from wind. If you are at risk from flooding it is important to get to high ground away from bodies of water and flood-prone areas. When there are high winds, then they recommend sheltering in place in a sturdy structure away from windows and doors. Following evacuation orders from local emergency managers is also a critical step for safety.

Property Values#

Research suggests that a high-risk flood zone designation reduces property value. In general, the negative impact on property value increases as the risk level increases but also varies widely by geographic location. In a meta-analysis of 19 case studies, researchers found that for every 1% increase in flood risk, there was a 0.6% decrease in the sales price of properties in coastal areas.

In contrast, some research also suggests that home prices can rise up to a maximum of 3-4% after three years in coastal cities following hurricane strikes. This increase is generally interpreted as a result of the decrease in the supply of homes that results from the destruction of properties during hurricanes.

What You Can Do#

Know the risks associated with your property and know the insurance options that are available. The Federal Emergency Management Agency (FEMA) maintains an online flood map service center that is a public source of flood hazard information including address specific flood zone information. The National Weather Service produces storm surge hazard maps that can be used to predict storm surge risk for a region based on hurricane category.

Standard homeowners insurance does not cover flooding and in high-risk coastal states, it does not cover damage caused by wind. Evaluate your risk and coverage to make sure your home is properly insured. The Insurance Information Institute provides detailed guidelines for evaluating insurance needs.

Retrofitting your home to protect it from flood and wind damage is another option. There are six general retrofitting methods recommended by FEMA to protect from flooding including elevating, moving, demolishing and rebuilding, wet floodproofing to make portions of a home resistant to flood damage, dry floodproofing to prevent water from entering, and building barrier systems. Similarly, FEMA recommends three retrofitting methods to protect from wind damage including improvements to roofing, siding, windows, doors, and load path connections (specific types of straps, brackets, and bolts). FEMA and some state agencies provide grants to help pay for some of these retrofitting methods under some circumstances.

AreaHub’s Knowledge Center is updated regularly and provides information drawing upon scientific studies and sources.

Sources#

Find information for climate, natural, and environmental hazards in the United States with a free AreaHub report. In just a few seconds, access data about 18 potential dangers in your area, like severe floods, toxic waste sites and more.

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