Citizen scientist breaks Louisiana rainfall record
The NASA-sponsored CoCoRaHS project volunteer recorded the historic precipitation, which experts say has a less than one-in-a-thousand-year probability of occurrence.
Matt Carnicle, a volunteer for the NASA-sponsored Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS), has recorded a new all-time rainfall record for Louisiana. On June 18, 2026, Carnicle measured 29.06 inches of precipitation in his backyard, surpassing the previous state record of 22.00 inches set in 1962. The rainfall occurred in less than 12 hours.
Carnicle, who joined the project through a storm-spotter class, described his participation as a regular hobby rather than a pursuit of records. He stated he simply reports the data found in his gauge, whether it is zero or a significant amount. His involvement extends to the network’s research into hail melt rates in the Gulf States, a project that compares satellite estimates of cloud stone sizes with ground measurements provided by volunteers.
The measurement has been validated by Louisiana State Climatologist Jay Grymes and representatives from the National Weather Service. According to Grymes, an event of this magnitude in the region is statistically rare, with a probability of occurring less than once in a thousand years. The data collected by CoCoRaHS is openly available and used by scientists to improve weather forecasting, inform water management, and trigger severe weather warnings.
To participate in the network, volunteers must use a specific manual gauge approved by the National Weather Service, which is precise to the nearest one-hundredth of an inch. Automated gauges are not accepted. Carnicle purchased a standardized gauge to ensure his data met the project’s rigorous standards for accuracy.
While the measurement is validated by state and federal officials, official verification and documentation are pending. A National Oceanic and Atmospheric Administration (NOAA) committee is scheduled to convene in the coming months to formally review and document the new record. Hawaii currently holds the national 24-hour rainfall record with 49.69 inches.
