Each spring, IBHS deploys the only active field research team dedicated to study hailstorms. The program goals are:
- To provide data to guide and improve laboratory hail testing.
- To map hailswaths to help verify and improve radar-based hail detection.
- To determine the environmental conditions that influence hail strength, hailstone concentrations, and ultimately the impact to homes & businesses.
- To evaluate regional differences in hailstone and hailstorm characteristics.
Field Research Insights
After 693 days and completed vaccine protocols, the IBHS Hail Field Study returned to operations, bringing along impact disdrometers and hail crushers, and working to understand the environmental characteristics influencing hailstone strength. The team also 3D-scanned a 6.4-inch hailstone in Hondo, Texas, that was saved by a homeowner following an April 28 hailstorm near San Antonio.
The team plans to return to the field in June for a second mission in coordination with a pilot National Center for Atmospheric Research (NCAR) project testing new technologies to observe hail with ground truth verification from IBHS.
Three field team deployments continued the push to better understand hail size distributions and continued IBHS’s contribution to radar hail detection research as we mapped the details of hailswaths. Teams collected 9 quality datasets.
The Record Hail Quick Response Team 3D scanned Colorado’s largest recorded hail stone and 6 giant hailstones in Arkansas. The Colorado stone fell August 13 and measured 4.83” in diameter.
The field team conducted 1 mission to the Central Plains and successfully collected 3 high quality hailswath data sets.
Following a severe storm on March 19 in Cullman, Alabama, IBHS established the Record Hail Quick Response Team. IBHS provided support to the National Weather Service and the Southeast Regional Climate Center to document what is believed to be the largest hailstone ever to have fallen in Alabama, and one of the three largest ever documented east of the Mississippi River. At 5⅜ inches (13.665 cm) at its largest measurement and approximately 0.6 pounds, its total volume was approximately 20 cubic inches (about the volume of a soda can).
2017 marked a shift in the IBHS hail field research program from individual hailstones to hailstorms and their hailswaths. This was the first year the full fleet of hail impact disdrometers were used in the field. IBHS maintains the only deployable instrument network dedicated to measuring hail impacts in the world. The team collected 5 quality swath cases. Using 3D Laser Scanning Technology to Create Digital Models of Hailstones (July 2017 Bulletin).
The field team debuted a new 3D scanner to collect digital models of natural hailstones. These models have been used to
- Revolutionize our understanding of hailstone aerodynamics leading to new insights into how fast hail falls and the energy it has when it impacts our built environment
- Preserve record setting hailstones for future research
- Improve our understanding of how radar “sees” hailstones compared to other precipitation types
- Help educate members, students, and other scientists on hailstone shapes
IBHS initiated a new collaboration with the University of Oklahoma using mobile Doppler radars marking the first-time mobile radar data were collected simultaneously over hail impact disdrometer measurements.
The field team deployed its first set of four of impact disdrometers to measure the hail size distribution and impact energy of falling hailstones. IBHS published the first peer-reviewed paper on hailstone strength setting the foundation for what would become the IBHS Hail Impact Test standard in 2019. Published: Evaluating Hail Damage Using Property Insurance Claims Data.
The field team collected data on 1,636 hailstones to build up the database of hailstones to establish hail lab testing capabilities and field tested two impact disdrometer prototypes. In collaboration with the National Center for Atmospheric Research (NCAR), IBHS modernized hail aerodynamic theory leading to simple hail diameter to impact energy relationships. IBHS initiated an ongoing collaboration with Penn State University to allow students to participate in the field study missions.
The field team collected data on 658 hailstones, initiated research collaboration with State Farm Insurance, and used hail strength data to improve impact tests at the IBHS Research Center. Field study data was used to recreate a full-scale indoor hailstorm at the Research Center.
The pilot study was the first known attempt to measure the hardness or compressive strength of natural hailstones. The field team collected data on 239 hailstones using a compressive force device developed by IBHS.