Examples of ground-based hail, rain, and wind sensor networks operating in real-time

Understory builds and deploys internet-connected weather stations that detect hail, rain, wind, and other weather events where the risk to life and property is the greatest - directly at the earth's surface. Our stations are unique in that they provide real-time, industrial-grade measurements of hail momentum and impact angle. They also measure rainfall, wind speed and direction, temperature, humidity, and pressure. Access to our data is free for academic research. In this contribution, we give a high-level overview of the physics behind our technology, the technical capabilities of our stations, and the accuracy of our sensors. In particular, we emphasize our unique ability to detect hail. Evidence from laboratory and field experiments demonstrates our success in detecting and measuring hailstone impacts separated by as little as 10 milliseconds. This measurement includes hailstone momentum and angle of impact. In 2017, Understory's full deployment across the Dallas/Fort Worth area will be approximately 150 sensors covering 2,000 sq mi. We will present results from the 2017 storm season where our stations collectively detected and measured the momentum and estimated impact angle and size of hundreds of hail strikes. By blanketing a metro area with these stations, we can get a better measurement of how mesoscale systems affect a city, accurately determine where hail fell, and assess the potential damage from the storm.