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Time to Re-Evaluate Hurricane Classification

Wind is not the only issue.

By now, just about anyone who can be impacted by a hurricane knows the the classifications of Levels 1 through 5. These levels are based on wind speeds.

 

Category Sustained Winds Types of Damage Due to Hurricane Winds
1 74-95 mph
64-82 kt
119-153 km/h
Very dangerous winds will produce some damage: Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.
2 96-110 mph
83-95 kt
154-177 km/h
Extremely dangerous winds will cause extensive damage: Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.
3
(major)
111-129 mph
96-112 kt
178-208 km/h
Devastating damage will occur: Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.
4
(major)
130-156 mph
113-136 kt
209-251 km/h
Catastrophic damage will occur: Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
5
(major)
157 mph or higher
137 kt or higher
252 km/h or higher
Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
But there are two other causes of hurricane and even tropical storm damage and deaths. The first being storm surge, which is when the ocean is propelled inland by the wind. This is what happened in Superstorm Sandy, with the hurricane making landfall at high tide. With sea rise now also becoming a hazard, storm surge is even more dangerous, yet not part of the hurricane warning.

Then there is rainfall that comes with the hurricane and tropical storms. Normally the rainfall has been measured in inches. With the most recent Hurricane Sally and Hurricane Harvey, we had rainfall measured in feet. 

Rainfall and storm surge need to be factored into the formula for categorizing hurricanes. I know this is an academic issue for some, but we need a way to warn the public that it is simple and it is not just wind that is causing damages and deaths from these storms. 

Eric Holdeman is a contributing writer for Emergency Management magazine and is the former director of the King County, Wash., Office of Emergency Management.