HYSPLIT Aids Ongoing Emergency Response Efforts in Deer Park, Texas

March 2019

Weather forecasters and emergency management personnel in Houston, Texas, are utilizing ARL’s HYSPLIT model to ensure public safety following a fire and subsequent leak at a petrochemicals storage facility in the nearby suburb of Deer Park. The fire began in a single storage tank on March 17 and spread to six other tanks before finally being fully extinguished on March 20. Highly-flammable chemicals used to make gasoline and other volatile products filled the tanks, resulting in the massive chemical fire that filled the skies with flames and smoke for more than three days, triggering multiple shelter-in-place orders.

Weather Forecast Officers in the National Weather Service’s Houston office provided HYSPLIT runs to local and state emergency management and other partners such as the Interagency Modeling and Atmospheric Assessment Center (IMAAC) every four hours during the event. HYSPLIT simulations are based on weather conditions, and are key to understanding how, where, and when pollutants – in this case, the smoke plume and the chemical vapors escaping from the damaged tanks – are transported, dispersed, and deposited.

The IMAAC, a Federal partnership that coordinates and disseminates atmospheric and dispersion modeling and hazard prediction products, was activated on March 19. All seven partner agencies have capabilities and/or responsibilities for plume modeling, enabling critical predictions of hazards associated with atmospheric releases. IMAAC is led by the Federal Emergency Management Agency and includes NOAA, the Department of Defense, the Department of Energy / National Nuclear Security Administration, Department of Health and Human Services, Environmental Protection Agency, and Nuclear Regulatory Commission.


HYSPLIT is a state‐of‐the‐art analytical tool initially developed by ARL over 30 years ago to produce operational and research‐grade dispersion products. Thanks to continual development and enhancements, HYSPLIT remains one of the most widely used models for atmospheric trajectory and dispersion calculations; successfully answering the fundamental questions: where did it come from, where is it going, and where is it hazardous? For more information, please visit: HYSPLIT Brochure (updated 8/2021)

Graphic depicting the location of the fire and modeled concentrations of the smoke footprint color coded for high or low concentration. Extends West from near Deer Park, across Houston, to/past Cypress, TX.
Probable smoke plume dispersion derived from HYSPLIT. Credit: NOAA NWS
Storage Tank fire at Deer Park, Texas on March 19, 2019, lasted for over a week, with ARL providing HYSPLIT runs daily. (Image Credit: EPA)
HYSPLIT logo. Black letters with the dot on the i as a colored plume.