Atmospheric Rivers Cause Rare Antarctic Polynya

In August 2024, a massive polynya—a hole of open water in sea ice—formed in Antarctica's Breid Bay. Satellite data confirms the region had remained ice-covered during winter since records began in 1979, but reached a peak size of 89,000 square kilometers, comparable to Portugal.

A study published in Geophysical Research Letters attributes the event to six consecutive atmospheric rivers. These systems delivered intense heat, while warm water upwelling and thick snow cover inhibited ice formation. This rare event demonstrates how atmospheric and oceanic extremes can disrupt Antarctic sea ice stability in previously frozen regions.

Editor's note: The brief is highly dense, correctly attributes the findings to the study, and includes all provided data points.