HURRICANE ANDREW'S LANDFALL IN SOUTH FLORIDA

Principal Investigator: Dr. Mark D. Powell
Collaborating scientist(s):
Samuel H. Houston

Dr. Timothy Reinhold

Objective: To reconstruct Hurricane Andrew's wind field at landfall and examine its decay as it progresses across south Florida.

Rationale: Immediately following Andrew, great interest arose regarding the magnitude and extent of the winds responsible for widespread damage and localized swaths of destruction. Unsubstantiated rumors circulated in the media of extreme sustained winds "clocked" anywhere from 150- 214 mph at several locations (the Pioneer Museum, Turkey Point nuclear power plant, Homestead Air Force Base, and an Army communications facility) where wind records were non-existent or incomplete. These rumors take on a life of their own and still persist with the public; many residents feel that they have survived a storm with winds much worse than actually occurred. Hence it is important that a careful, scientific examination of all the data be conducted to determine Andrew's strength at landfall.

Method: All available wind data associated with Hurricane Andrew's passage were analyzed for periods corresponding to landfall south of Miami and emergence from southwest Florida. The data were processed to conform to a common observing framework for height, exposure and averaging period. This framework corresponds to that used by the National Hurricane Center for warnings and advisories. All data were then subjected to quality control and objectively analyzed.

Accomplishment: At landfall in southeast Florida, maximum sustained (1 min) surface wind speeds (VM1) reached just over 60 ms-1 in the northern eyewall over land (Figure 1); by the time Andrew exited the Florida peninsula, the peak value of VM1 over land decreased to 40-45 ms-1 (Figure 2). Radar reflectivity observations from Tampa and Melbourne could not support an obvious correlation of convective cell development with coastal convergence during landfall on the southeast coast. On the southwest coast however, convective cell development in the southern eyewall was supported by a coastal convergence maximum. Comparison of the wind swath with two independent Fujita-scale damage maps indicated that peak swath speeds compared well with speed equivalents in the worst damaged areas but were higher than equivalents in moderately damaged areas. Comparison of the analysis maximum wind swath with an engineering survey of damaged homes suggests that homes exposed to a wide range of wind directions while subjected to high wind speeds suffered the most damage. Potential real-time applications of wind field products include warning dissemination, emergency management, storm surge and wave forecasting, and wind engineering.

Key reference:
M. D. Powell, S. H. Houston, and T. Reinhold, 1995: Hurricane Andrew's landfall in south Florida. Part I: Standardizing measurements for documentation of surface wind fields. Accepted, Weather and Forecasting.

M. D. Powell, and S. H. Houston, 1995: Hurricane Andrew's Wind Field at Landfall in South Florida. Part II: Surface wind fields and potential real-time applications. Accepted, Weather and Forecasting.

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