Ice concentration is measured in tenths. What concentration range of ice corresponds to "Close Pack"?
Official USCG Answer & Rule Citation
Correct Answer: Option A — 7 - 8 tenths
Ice concentration is reported in tenths of coverage. According to the World Meteorological Organization (WMO) and USCG ice navigation standards, 'Close Pack' ice is defined as a concentration of 7 to 8 tenths, where ice floes are mostly in contact and navigation becomes significantly restricted.
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