Severe Weather 101

Hail Detection

Hail can be detected using radar. On Doppler radar, hail generally sends a return signal that looks like extremely heavy rainfall.

Dual-polarization radar technology, used by the NWS can help tell the difference between hail, ice pellets and rain, and even determine hail size.

What we do: NSSL's Hydrometeor Classification Algorithm (HCA) uses dual-polarization technology to automatically sort between ten types of radar echoes including big raindrops and hail. This helps the forecaster quickly assess the precipitation event and better forecast how much will fall.

NSSL's On-Demand, a web-based tool helps confirm when and where severe weather occurred by mapping circulations or hail detected by radar on Google Earth satellite images. NWS forecasters can quickly review warnings and check their accuracy with this system. Emergency responders and damage surveyors have also used On-Demand to produce high-resolution street maps of affected areas, so they can more effectively begin rescue and recovery efforts and damage assessments.

NSSL collaborates with research companies to help the insurance industry anticipate and react to hail and other storm damage, saving time and money. Under the terms of multi-year joint research projects, NSSL provides data to partnering companies, which in turn provide critical insurance industry feedback and quality control assessments to improve NSSL's algorithms.