Estimation of Global Increase of Radiation Dose Rates During the Ground Level Enhancement on 11–12 November 2025 Using WASAVIES

Abstract WArning System for AVIation Exposure to Solar energetic particles (WASAVIES) is a physics‐based nowcasting system designed to support warning operations for aviation exposure to solar energetic particles (SEPs) by providing near‐real‐time global SEP dose‐rate estimates. On 11 November 2025, ground level enhancement GLE77 occurred and successfully triggered the SEP mode of WASAVIES, demonstrating fully autonomous initiation of global SEP dose‐rate nowcasts during an extreme space‐weather event. The real‐time analysis, however, was partially degraded during parts of the event due to irregular behavior in some neutron monitor (NM) data streams and evolving background conditions. We therefore performed a post‐event reanalysis using a patched version of the operational algorithm to mitigate these issues. Our analysis indicates that GLE77 consisted of multiple peaks and maintained an unusually low rigidity spectral index (as low as 4) for several hours, suggesting that it was the hardest‐spectrum GLE since 2000. The analysis also indicates that the estimated global maximum effective dose rate (including the galactic cosmic‐ray contribution) briefly exceeded the International Civil Aviation Organization Moderate advisory threshold (30 μSv/h) at altitudes of 14 km (∼FL460) and above, but the exceedance was short‐lived (∼10 min) and limited in magnitude and geographic extent. This finding confirms that GLE77 did not warrant major operational responses such as route or altitude changes. Overall, these results validate the operational potential of WASAVIES and identify key upgrades needed to ensure stable, reliable nowcasts for future extreme events.