We provide the services necessary to allocate damages between wind and flood in situation where damage is inflicted by a windstorm, such as a hurricane, and then a flood, such as storm surge, occurs.
Our approach is to start by determining the depth of the flood, and timing of the arrival of damaging winds and flooding, and inspect facilities to determine the nature and extent of damage inflicted by a storm.
Flood Depth: Flood depth is an important determinant in allocating damages, because damage above the flood elevation is typically the result of wind damage, while damage below the flood elevation may have been caused by wind prior to flooding, or by the flood alone. Depending upon information available, we determine flood depth by use of information from a variety of information sources, such as publicly available documentation from NOAA, FEMA and others, water marking and damage to facilities, and computer modeling. Sometimes it is also necessary to perform survey work to establish elevations of floors and equipment. Typically, there will be some variation in field data, so we treat this data statistically to determine its precision and variability, and correlate it to other data sources such as weather data and/or the results of computer modeling. All of this results in a determination of actual flood depth to a very high degree of scientific certainty.
Wind: High winds and floods both inflict damage by imposing loads that can damage or even rip components from buildings or industrial equipment. In allocating this type of damage between wind and flood, we study the timing of the arrival of damaging winds, and the arrival of flood waters. We get data about wind direction and velocity from public sources such as NOAA, FEMA or private weather data providers, and wind gauges that may exist in the vicinity. Frequently, we have to extrapolate, or model wind velocities and direction at a particular site by taking into account distance from measuring devices, plotted distance to a hurricanes eye, eye diameter.
Facility Condition: Our inspection of the facility provides information about the specific damage that has been suffered, but also allows us to determine the fragility of buildings, equipment, and components. This allows us to determine the magnitude of a wind, or the depth of flooding, or water flow that could have caused the damage. As the forces applied by winds and floods are not uniform, assessing the fragility of a facility allows us to better correlate the observed damage to allocate that damage to wind and flood. Frequently, we are also able to determine the direction of the forces that caused the damage so that this can help determine whether wind or flood is responsible for specific damage observed.
All of this results in a description of the velocity and direction of winds at the site, and the susceptibility of a facility to be damaged by the forces applied by the wind and flood, allowing a very accurate allocation of repair and restoration costs between wind and flood.
We also look at the chemistry of the rain water involved in the storm. The chemistry of rain water differs between inland storms and coastal storms. Rain water and wind-driven rain that accompany a hurricane in a coastal zone contain salt, and as such are more corrosive than the fresh water accompanying wind storms, such as thunderstorms, inland. In the absence of salt, typical restoration of equipment wetted by rain water alone is accomplished by drying to prevent corrosion and lubricating moving parts. Wind-driven rain during a hurricane in a coastal region that contains salt causes increased damage, and requires more cleaning to remove the salt. In addition, as high winds in coastal storms pick up salt from the ocean, the amount of salt in the atmosphere is greatly increased resulting in a more corrosive environment for equipment and buildings. During a wind storm, dirt, grit, debris and possibly chemicals, are picked up by wind and mixed with the rain, which can increase damage and increase clean-up costs.
When assessing damage to equipment, we determine the initial time of wetting. In the open, this coincides with the first arrival or rain. Inside a building, we determine the timing of damage to the building, and the subsequent wetting of equipment housed in the building.
Here are some examples of past projects that illustrate our approach.