Extreme Weather: Preparing for Tornadoes, Hailstorms, and the Hurricane Season
May 17, 2017
A round of storms, wind, hail, and isolated tornadoes, killing at least 14 people, impacted parts of the Midwest and South during the last weekend of April. On May 8, 2017, the city of Denver was impacted by a major hail event with widespread large hail damaging windows, vehicles, and other structures (see Figure 1 and Figure 2). Additionally, several major tornado events have already occurred in 2017 across the central region of the United States causing severe damage and loss of life.

Hurricane Figure 1

Figure 1. Three-dimensional view of Denver thunderstorm on May 8, 2017 at 5:20 PM MDT. The color shading represents radar reflectivity levels. The portion of the thunderstorm in which hail is present is shown by the purple color shaded region.

Figure 2

Figure 2. Time sequence of vertical cross sections of the Denver Thunderstorm on May 8, 2017. As is clearly evident in this figure, the hail zone height collapsed as it fell out of the thunderstorm. Also note the anvil-type cloud structure extended well to the northeast with maximum cloud tops nearing 40,000 feet. These features are typical of strong thunderstorms. Radar reflectivity and many other radar parameters that can be used together to help identify where hail is reaching the ground and to estimate the hail stone sizes.

We are currently well into the severe tornado and hail season in the United States. Hurricane season will begin on June 1, and hurricane frequency reaches peak activity around September, when the chances for destructive wind and flooding from these storms are highest.

Exponent’s team of atmospheric scientists, engineers, industrial hygienists, and health consultants offers a select group of services to assist our clients in the event that a tornado, hailstorm, or hurricane strikes our borders.

How Exponent Can Help


Exponent’s services include:

  • Wind Engineering – We have helped owners of facilities in areas of high wind hazard quantify and mitigate their risks, and we have assisted insurance carriers investigate the cause(s) and differentiate damage mechanisms after storms (including hundreds of structures after Hurricane Katrina).
  • Meteorological Analysis – Exponent has strong capabilities and deep experience in meteorological analysis including state of the science numerical meteorological modeling, weather radar analysis and satellite imagery interpretation. Numerical meteorological modeling can be used to develop a high spatial and temporal resolution analysis of meteorological fields during the storm event that can be used to perform storm damage assessments. Meteorological model output can be coupled with Computational Fluid Dynamics models to determine the pressure forces on building structures and thus assess if structural damage is due to a particular storm event.
  • Health Effects Analysis – Exponent’s industrial hygienists and health consultants provide support related to health impacts from moisture and water intrusion, environmental mold, odors, and other related issues from furniture, consumer products; food and other materials.
  • Investigation of Structural and Architectural Damage – Exponent’s engineers work with adjusters to determine the nature and extent of damage, evaluate the contributions of perhaps several causal factors, and identify the most appropriate repairs.

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