Weather data is obtained or collected for the area where the facility is located in order to more accurately determine how a consequence for a given accident will affect the surroundings. Average temperatures, wind speeds, and the stability of the atmosphere can have a significant effect on vapor cloud dispersion. Some areas may have a lower average wind speed which may allow for larger vapor clouds to form. The stability class of the atmosphere effects how quickly the hazardous materials disperse. The weather data may play a large role in determining the site specific risk in an analysis. For additional information, read our paper on the importance of weather data.
A wind rose shows the average wind speed in all directions.
Notice the directional nature of the winds at this site.