by Mike Murphy - October 2005

What do hurricanes and financial performance have in common?  Past performance is no guarantee of future results.  While forecast models are probably more accurate than investment analysis, the actual results are all that really mean anything.  According to the National Hurricane Center (NHC), 76% of category 4 and 5 hurricanes strike either Florida or Texas. 

The NHC list of deadliest and costliest hurricanes 1900-2000 reveals several other facts. Ten of the twelve deadliest hurricanes were category 4 or higher. Large death totals were primarily a result of the 15-20 feet or greater storm surge.  Although half of the deadliest hurricanes were category 4 or higher, only one-sixth of the costliest hurricanes were that strong.  Only one of the deadliest hurricanes occurred but two-thirds of the costliest hurricanes occurred during the past 25 years.

Below are some relative facts from the National Hurricane Center (NHC) that may interest those who have not experienced a tropical storm or hurricane.  The states with the most frequent hurricane strikes from 1900-2004 by category are summarized as follows:                                                                                                                                          

During the same time, the combined tropical storm and hurricane (category 1-5) strike rate within 100 miles of Corpus Christi provides a better indicator of what to expect locally as shown below.                   

From 1900-2000 only 7 major (category 3-5) hurricanes have struck within 100 miles of Corpus Christi and all of these were in August or September.  Each of these major hurricanes are ranked by the NHC among the 65 most intense and half of these also have additional NHC distinction.  Vital statistics on these hurricanes are shown below.

Historically South Texas has experienced 10% of the major (3-5) hurricane strikes on the US mainland.  While no category 5 storms have made landfall within 100 miles of this area, there have also been numerous other tropical storms.

The 1919 hurricane was a direct strike, most intense and deadly with the highest tides at 16 feet above mean sea level.  The 1933 hurricane was also intense and deadly, making landfall closer to Brownsville.  Allen was unusually fast moving (15-20 knots) with the second lowest pressure ever in the Atlantic, Caribbean and Gulf.  Allen reached category 5 three times before making landfall between Corpus Christi and Brownsville with an estimated 15 foot tidal surge.  Beulah struck closer to Brownsville, recorded the second lowest pressure (923mb) ever in the Gulf with 7 foot tides in Corpus Christi.  Bret was considered small, making landfall between Corpus Christi and Brownsville as the first strike of any significance since the island development in Corpus Christi has taken place.  Carla was the most significant, ranking on all NHC measures.  Carla made landfall at Port Lavaca and tides at Port Aransas were 10.9 feet.  Celia was also small, fast moving and a direct hit at Aransas Pass with 9.2 foot tides at Port Aransas.  Celia was also the most costly Texas coast and last strike here of any major consequence.  The most unique feature about Celia was the rapid intensification (39mb pressure drop 15 hours before landfall) which was not forecast and 160 mph peak wind gusts from the West during landfall was also unusual.

So what good does all this do anyone?  None probably, this area is always susceptible to tropical storms or hurricanes any month of the season.  Some tropical storms have caused more problems than hurricanes so the risk is not necessarily lower.  The data available and forecast techniques can be used to make educated guesses and some historical basis may give comfort or concern.  One thing for certain, a major strike is long overdue for this area, it’s just a matter of when.  Advanced planning, preparation and early evacuation are definitely the safest way to weather these storms.  Several hurricane strikes since 2000 have been significant, especially in Florida and now Katrina in Louisiana.  Many of the major hurricanes during the past 5 years will likely lower the NHC rankings especially the most costly distinction measure.