Muy interesante. #Carta de hielo en el #hemisferio norte. #Cartografía. Año1946
“Published by the Hydrographic Office, US Navy, Washington DC”.
En el mapa se reflejan 5 tipos distintos de hielo y en la leyenda los describe de la siguiente manera:
-Permanent polar pack, inaccessible to navigation.
-Unnavigable sea and land-fast ice, occasionally penetrable by powerful icebreakers.
-Generally unnavigable sea and land-fast ice. Ice-breaker assistance normally required, although at times penetrable by heavily built vessels.
-Sea and land-fast ice generally navigable by heavily built vessels.
-Sea and land-fast ice generally navigable by unrein-forced vessels.