Computer Modeling of a High-Wind Episode in the Southern Joaquin Valley of California
Overview
The Defendants designed and installed temporary agricultural structures at two sites located approximately 23 miles apart in the Southern Joaquin Valley of California. A rain film system designed to protect from rain and manipulate temperature for production was designed and procured by the Owner. During a substantial storm on January 8-9, 2018, the rain firm system was substantially destroyed, but only at one of the two sites. The Owner of the agricultural production facilities initiated litigation against the Defendants, claiming that negligence in the design and construction of the temporary agricultural structures caused the failure of the rain film at one of the two sites.
EnviroComp's Role
EnviroComp was retained by the law firms representing the Defendants, i.e., the company that designed and constructed the shade/rain structures. Our work aimed at providing the most accurate possible reconstruction of wind speed and direction at the locations of interest during the hours of the high-wind episode.
We collected available meteorological data in the region, as shown in Figure 1 (yellow pins). These measurements provided some initial evidence of wind speed and direction in the region during the high-wind episode.
To obtain more precise results at the two sites of interest (indicated by red pins in Figure 1), we used the Weather Research & Forecast Model (WRF), a state-of-the-art mesoscale numerical weather prediction system designed for both atmospheric research and operational forecasting applications.
Our WRF simulations were performed over a period of 24 hours using four nested domains of 13.5 km, 4.5 km, 1.5 km, and 500 m, as shown in Figure 2. Two examples - at 2:30 am and 3 am - of WRF simulation results are presented in Figure 3, where black arrows show the wind vectors, and the darker colors indicate higher terrain elevations. The wind vectors show a very complex wind flow, with channeling effects and large spatial variations.
Our results and graphics were presented to a jury at trial and were key to the jury's understanding of how a rain film system installed on a temporary agricultural structure could and did fail in the absence of any structural design or installation defects. Our clients obtained a complete defense verdict.
Visuals
Figure 1 - Meteorological station (yellow pins) in the area of interest. Red pins indicate the sites where shade/rain structures failed.
Figure 2 - WRF modeling domains.
Figure 3 - Examples of WRF results for wind vectors at 2:30 am and 3 am on January 9, 2018.