Hurricane Harvey: Why Has It Been so Devastating?

Hurricane Harvey is going to go down in history as one of the most damaging and destructive hurricanes of all-time to hit the United States. Harvey was named by the National Hurricane Center when it was east of Barbados on August 17, but it weakened to a tropical wave while moving across the Caribbean. It passed over the Yucatan Peninsula, then intensified into a tropical storm while in the Bay of Campeche on August 23. The system underwent rapid intensification over the next several days, becoming a Category 4 hurricane (maximum sustained winds >= 130 mph) before making landfall near Port Aransas, TX during the evening of August 25. In doing so, it became the first Category 4 hurricane to make landfall in Texas since Carla in 1961 and the first to make landfall in the United States since Charley in 2004.

While Harvey caused some damage due to storm surge and high winds near its landfall location along the central Texas coastline, it will primarily be known for the massive amounts of rainfall that it dumped on the Houston metropolitan area. Over 2 feet of rainfall has fallen in a wide swath in the Houston metropolitan area (Figure 1), with some local areas reporting over 30” of rain through this morning. Unfortunately, more heavy rainfall on the order of 15-25” is expected over the next few days in the Houston metropolitan area. As of this morning, Brock Long, the Federal Emergency Management Agency director, estimated that 450,000 individuals are going to seek some sort of public assistance and 30,000 people will need to be sheltered temporarily.

The problem with Harvey is that it has been nearly stationary for several days, and its lack of motion is likely to continue through the middle of this week. While Harvey has been over land, it has been close enough to the Gulf of Mexico to ingest plenty of warm, moist Gulf air and fuel intense rain bands over land. In addition, a hurricane’s fuel source is warm ocean water, so while the center is over land, its large-scale circulation is receiving enough fuel to maintain some strength. While Harvey made landfall 60 hours ago, it is still a tropical storm, making it the longest-lived named storm after hurricane landfall in Texas on record (since 1851).

Harvey’s lack of movement can be attributed to areas of high pressure in the Southeast and in the western part of the United States (Figure 2). The circulation around these two areas of high pressure is preventing inland movement and have effectively stalled Harvey for the time being. This pattern is forecast to remain relatively stable for the next several days, and consequently, the official forecast from the National Hurricane Center does not have Harvey exiting the state of Texas until Thursday. 

NOAA Radar Estimate for Harvey
Figure 1: Radar estimated rainfall amounts (inches) from the National Oceanic and Atmospheric Administration Houston radar since Wednesday, August 23. Most of this rain has fallen over the past 48 hours. Figure courtesy of NOAA

Hurricane Harvey Air Pattern
Figure 2: Large-scale circulation pattern that is keeping Harvey stalled along the Texas coast. Areas of high pressure to the east and northwest of Harvey are forcing the storm to remain at a near standstill. Figure courtesy of NOAA.  

Our best wishes go out to all of those affected by Hurricane Harvey. We understand the significant impact this storm brings to both your business and personal lives, so please take care and stay safe.

About the Author:
Dr. Phil Klotzbach has received national and international attention for his work in researching weather patterns and forecasting hurricanes. For the past 10 years, Dr. Klotzbach has been lead author on Colorado State University's Atlantic basin hurricane forecasts, which were founded by his late esteemed colleague Dr. William Gray.   

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