Hurricane Harvey, which lasted from mid-August to early September 2017, was a devastating weather event that impacted the U.S. Gulf Coast, primarily Texas. It rapidly intensified in the Gulf of Mexico, becoming the first major hurricane to make landfall in the United States since 2005. Examining the specific wind speed data recorded by meteorologists helps illustrate the storm’s power and destruction.
Peak Intensity and Landfall Wind Speed
Hurricane Harvey reached its maximum strength just hours before its initial landfall on the Texas coast. The maximum sustained wind speed recorded was 130 miles per hour. This peak intensity occurred when the storm’s center crossed the northern end of San Jose Island near Rockport, Texas, at 10 P.M. CDT on August 25, 2017.
The storm’s minimum central pressure dropped to 937 millibars at the time of the first landfall, which is a direct indicator of hurricane strength. A few hours later, the storm made a second landfall on the Texas mainland near Holiday Beach, having slightly weakened but still maintaining powerful winds.
The official maximum sustained wind speed of 130 mph is an estimate based on data from reconnaissance aircraft and surface observations. Wind instruments on the ground often fail or are destroyed before recording the highest speeds in the most intense part of the storm, the eyewall. The highest measured peak wind gust was 145 mph, recorded at the Aransas County Airport in Rockport.
Categorizing the Wind: The Saffir-Simpson Scale
The measured sustained wind speed of 130 mph placed Hurricane Harvey into a specific classification on the Saffir-Simpson Hurricane Wind Scale (SSHWS). This scale is used by meteorologists to categorize hurricanes based on their one-minute maximum sustained wind speed. The scale ranges from Category 1, representing the lowest hurricane-force winds, up to Category 5, representing the highest.
A sustained wind speed of 130 mph meant Harvey was a Category 4 hurricane when it made landfall. The Category 4 designation is defined by wind speeds ranging from 130 to 156 miles per hour. This level of wind is capable of causing catastrophic damage, including the complete destruction of mobile homes and significant structural damage to well-built frame homes.
When discussing hurricane intensity, it is necessary to differentiate between sustained winds and wind gusts. Sustained winds are the average speed measured over a one-minute period, which is the standard used for the Saffir-Simpson Scale. Wind gusts are short, sudden bursts of faster wind. The 145 mph gust recorded near Rockport shows that localized wind speeds were higher than the official sustained speed.
Wind Speed vs. Rainfall: Harvey’s Primary Threat
While Harvey’s wind speed was destructive, its historical significance is tied to a different element: the unprecedented rainfall. The damage caused by high winds, such as downed power lines and structural failures, contrasted sharply with the widespread damage caused by water. The storm’s most catastrophic threat was the water it dumped over the Texas coast and the Houston metro area.
The storm’s forward motion essentially stalled after landfall due to a collapse in the steering currents in the upper atmosphere. This lack of movement caused Harvey to linger over the region for days, drawing moisture from the warm Gulf of Mexico and releasing continuous, torrential rain. This phenomenon led to historic rainfall totals across southeastern Texas.
The highest storm total rainfall report was 60.58 inches near Nederland, Texas, setting a new record for the highest amount of rain from a single tropical cyclone in the continental United States. Large areas of the Houston metropolitan region received over 40 inches of rain, resulting in catastrophic and widespread flooding. The volume of water caused thousands of homes to be inundated and led to record river crests across the region.