Dr. Halvorsen had watched the ice shelf retreat for thirty years. Each decade, the seaward edge — the rightmost column of her survey grid — calved away, one vertical strip at a time. The shelf that had once filled her entire grid was down to three columns by her third survey. Then came the polar vortex winter of '09. For the first and only time in her career, the shelf grew back: a full column of new ice reformed on the seaward edge, pushed out by the cold. She published the anomaly and retired. The next survey showed the retreat had resumed, the brief reprieve already gone.