Hurricane Categories and Related Damage November 28, 2017 – Posted in: Blog

Everyone knows hurricanes are among the most powerful storms experienced on earth. We’ve all seen videos of weather forecasters leaning into the wind, and we’ve all seen images of the post-hurricane damage. But what makes a hurricane a hurricane? And how are hurricane categories settled upon? If you’ve ever wondered about hurricanes and their characteristics, here’s a look at hurricane damage by category.

Hurricane Damage by Category - Micrographic

Hurricane Categories Explained

Hurricanes are categorized using the Saffir-Simpson Hurricane Wind Scale, which rates hurricanes from 1 to 5 — all based on the “sustained wind speed” that a hurricane brings. Here are the 5 categories, including their sustained wind speeds and the damage they’re likely to create:

  • Category 1: Hurricanes feature sustained winds between 74 and 95 miles per hour. These hurricanes are dangerous and could produce some damage to roofs, shingles, siding and gutters. Large trees and branches may snap and topple, and power lines and electric grids may also experience damage. In 1985, Hurricane Danny made landfall in Lake Charles, LA, which led to tornado outbreaks and flash flooding that caused about $100 million damage.
  • Category 2: Hurricanes feature sustained winds between 96 and 110 miles per hour. Again, these hurricanes are dangerous and will produce some damage, though the loss of life and severe damage is usually limited. In 1995, Hurricane Erin hit Florida’s panhandle as a Category 2 hurricane, where it damaged ships, crops and trees, causing about $700 million in overall damage.
  • Category 3: Hurricanes are the first of the “major” hurricanes, with sustained wind speeds between 111 and 129 miles per hour. Roofs may fly off homes entirely, and trees may be uprooted. Hurricane Katrina was a Category 3 hurricane when it struck New Orleans in 2005. Nearly 2,000 people were killed, and damages totaled $81 billion.
  • Category 4: Hurricanes arrive with sustained wind speeds of 130 to 156 miles per hour. These hurricanes can down homes and trees and leave areas uninhabitable for weeks or months. The Great Galveston Hurricane of 1900 was a Category 4 storm. It made landfall along the Texas coast near Houston, and its 15-foot storm surge destroyed 3,500 homes and buildings, while also killing 8,000 people. It’s the deadliest hurricane in American history.
  • Category 5: Hurricanes and their winds of 157 miles per hour or more will destroy a large percentage of homes in the areas where they land. Power outages are lengthy, and the area can’t be inhabited for months afterward in many cases. Hurricane Andrew was a Category 5 storm when it struck South Florida in 1992, leaving 54 dead and rendering $26.5 billion in damage. The area was largely evacuated before the hurricane hit, which prevented greater loss of life.

As you can tell from the loss of life and damage statistics above, there’s no direct correlation between higher sustained winds and greater damage. It also matters how many people live in an area that is struck, as well as how many people are still in the area before the hurricane hits.

For example, the Galveston Hurricane of 1900 was far deadlier than Hurricane Andrew in 1992 simply because, with Hurricane Andrew, South Florida had forewarning and was able to evacuate before the storm hit. Also, Hurricane Katrina was far costlier to repair than Hurricane Andrew because of the unique characteristics of the area where it made landfall.

Hurricane categories can provide a rough estimate of how much damage and loss of life to expect, but it will vary based on the specific areas where hurricanes hit.

Flooding from Hurricanes

Hurricanes are known for their torrential rains, powerful winds and the devastation that they leave behind. We’ve seen some of the worst hurricane flooding in history in just the past year. How do hurricanes cause flooding, and what do the storm’s categories have to do with the amount of flooding they can cause?

We know that hurricanes can bring massive winds and rains, leaving destruction in their wake, but how do hurricanes actually cause flooding?

Hurricane flooding happens in one of two ways — storm surge and rain.

How Do Hurricanes Cause Flooding?

The most common cause of hurricane flooding is storm surge. Storm surge is caused by wind and air pressure pushing sea water onto coastal lands. It is often preceded by a dramatic drop in coastal water depths — before Hurricane Irma made landfall in September 2017, the receding waters were so dramatic that they left manatees stranded in the Tampa Bay area when the water disappeared from around them.

When the storm makes landfall, it pushes all that water ahead of it onto the land, creating devastating coastal flooding.

This is one of the most common causes of flooding from hurricanes, but hurricanes aren’t the only thing that can cause storm surge — blizzards and winter storms making landfall also create this dangerous flooding.

The other common cause of hurricane flooding is rain. Hurricanes get the majority of their energy and rain from warm ocean waters. If they move quickly, they often won’t drop a lot of rain — damage from fast-moving storms primarily comes from the high winds.

If the storm moves slowly or slows down once it makes landfall, then it has the potential to unleash a deluge. The latter is what happened with Hurricane Harvey in September of 2017. The storm was a Category 4 when it made landfall, but weakened to tropical storm strength almost as soon as it hit Texas. Unfortunately, this dramatic weakening did nothing to dissipate the heavy rain clouds that were left over, and the storm stalled out. It sat in the same place for nearly 5 days, raining.

Flooding from hurricanes, especially in areas that aren’t prepared for massive rainfall, can be devastating. At the time of this writing, it has been nearly 6 months since Harvey made landfall, and many families and businesses are still picking up the pieces left behind by this record-breaking storm.

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