National Hurricane Preparedness Week May 5-11, 2019

How do hurricanes get their categories?

May 5 to 11 is National Hurricane Preparedness Week, a time for raising awareness about the dangers of hurricanes and the importance of preparing for hurricane season.

If you’ve followed media coverage of major hurricanes, you’ve probably heard reporters discuss storms in terms of categories ranging from one to five. But do you know where these numbers come from or what they really mean?

Since 1970, hurricanes have been categorized according to the Saffir-Simpson Hurricane Wind Scale, which measures the sustained windspeeds of a storm in miles per hour. This scale puts hurricanes in categories ranging from one to five, with five being most severe.

Category one and two storms are considered minor hurricanes but are still very dangerous. People and property are at risk from flying debris, and affected areas are likely to lose power.

Category three storms are considered major, with property damage highly probable. Affected areas are likely to lose access to water and electricity, and flooding may cause water contamination for many days.

Category four and five storms are known as super typhoons. All structures are at risk of severe damage and possible roof failure. Flooding may reach far inland, and trees are likely to be uprooted or debarked. Affected areas typically lose power and water, sometimes for several months.

These categories are very useful for understanding how dangerous incoming hurricanes are likely to be. It’s important to note that the Saffir-Simpson scale only considers wind speeds and doesn’t account for the risk factors associated with rain or storm surges. Category one and two storms can still be extremely dangerous if they result in extreme rainfall and flooding.

For more information about Hurricane Preparedness Week, go to nhc.noaa.gov.