CBV, Playa Ancha/ Valparaiso Radio, Chile, broadcasts this Chilean Navy ice chart daily around 2215 UTC. Squiggly lines are ice edges.
Antarctic sea ice can develop rapidly and lock in ships, eventually crushing them. One famous example is the 1915 loss of the British exploration vessel Endurance, leading to the dramatic rescue of the Shackleton expedition.
All fax signals are tuned 1.9 kHz lower than their listed frequencies.