June 25, 2025

On Tuesday, June 17 NOAA’s Air Resources Laboratory (ARL) and the National Centers for Environmental Prediction (NCEP) conducted an exercise tracking a hypothetical leak at a nuclear power plant in Canada.

ARL and the National Weather Service’s NCEP were designated as a Regional Specialized Meteorological Center (RSMC) for the Washington region in 1993 by the World Meteorological Organization (WMO). The RSMCs are part of a system for early warning messaging tracking fallout from a nuclear accident and were a result of the International Atomic Energy Agency reaching out to WMO after the Chernobyl accident in 1986.

Since nuclear incidents are very rare. RSMCs conduct monthly exercises to practice the workflow and ensure each region is ready in the event of an actual emergency. RSMC Washington and RSMC Montreal are paired and run exercises together for the U.S. and Canada and take turns with the other centers acting as the lead each time. All ten RSMCs are invited to participate and take their own turns as lead. RSMCs Washington and Montreal led last week’s exercise and chose a nuclear powerplant in Pickering, Ontario as the site of the hypothetical incident. They designated it as an eight-hour nuclear release that began at 4:00 AM ET. 

As the exercise began, NCEP’s Senior Duty Meteorologist ran ARL’s HYSPLIT model, using a version developed specifically for the National Weather Service and the current meteorological conditions. ARL scientist Alice Crawford checked the model results, which forecast out 72 hours, and showed the amount and path of travel of the hypothetical nuclear material. RSMCs Washington and Montreal drafted a joint summary of the model results, the finalized summary was published on the RSMC website along with each center’s model results from the exercise. 

These exercises are a critical piece of the WMO’s messaging system. They ensure that everyone knows what needs to be done, who is responsible for what, and who needs to communicate with who during an actual event. RSMC Washington’s participation is organized by ARL scientist Tianfeng Chai who takes turns with Hyun Cheol Kim and Alice Crawford to run ARL’s part each month. The RSMC website is not available to the public, but is accessible to those who would need to access it in the event of a real incident.