lowered from a helicopter during a cliffside rescue exercise in Washington state.
The Coast Guard is also responsible for breaking the ice in northern ports for tankers. Here, a Coast Guard cutter breaks the ice near Nome, Alaska, so that a Russian tanker could offload almost 1.3 million gallons of petroleum products to the city.
Cutting through the ice is a team effort. Here, a Coast Guard MH-65 Dolphin helicopter ascends from Nome after providing ice reconnaissance during the escort of the Russian tanker.
The Coast Guard specialises in these kinds of icy conditions. Here's the USCG Polar Star in Antarctica.
Here, Coast Guard crew members aboard the Polar Star help to free an Australian fishing vessel trapped in Antarctic ice.
The Coast Guard keeps open fast-freezing shipping lanes in the Great Lakes as well. Here, crew members from the USCG Cutter Bristol Bay take a dip in Lake Erie at sunset, with a Canadian coast-guard ship in the background. The two vessels created a path through the ice early in the day.
The Coast Guard helps to conduct scientific experiments over the Arctic as well. In this photo, crew members deploy probes that measure sea temperature, salinity, and density to gain a better understanding of the Arctic during the summer season.
Members of an ice-rescue team survey an ice sheet before allowing crew and passengers of a vessel to disembark.
The Coast Guard constantly looks to improve its capabilities. Here, Arktos Developments displays its amphibious Arctic craft, with heavy tank-style treads that can move through snow.
Keeping equipment in working order is difficult in Alaska, and a matter of life and death for the Coast Guard. Here, a distress-team leader clears ice and snow from solar panels that power a microwave link site for communications in western Alaska.
Another key job of the Coast Guard is to maintain navigation service aids throughout the waters around Alaska. Here, an electronics technician is lowered to a communication and navigation station on an island in Cold Bay.
The Coast Guard helps preserve the environment, too. Part of the branch's job is fisheries enforcement and making sure that vessels don't exceed their legal fishing limit to ensure that the ecosystem stays intact.
Outside of Alaska, the Coast Guard fills a multitude of other roles, including maritime law enforcement. Here, south of Puerto Rico, Coast Guard aircraft follow and identify two alleged smugglers.
The Coast Guard is also tasked with interdicting drugs that may be smuggled into the US along various waterways.
A Coast Guard Cutter Stratton boarding team investigates a self-propelled semisubmersible interdicted in international waters off the coast of Central America on July 19, 2015.
The Coast Guard also plays a key role in ensuring that the nation's most important ports are secure. Here, Coast Guard members demonstrate tactical small-boat operations in Honolulu Harbour.
In Puget Sound, the Coast Guard carries out frequent security operations to protect ferries that shuttle more than 22 million people in and out of Seattle each year.
And in New York Harbour, the Coast Guard ensures that shipping lanes stay open and protects against any potential acts of terrorism.
A boat crew from Coast Guard Station Port Canaveral, Florida, enforces a safety and security zone during a rocket launch off the coast of Cape Canaveral on June 24, 2016.
The Coast Guard operates internationally as well. In Shanghai, for instance, members of the US Coast Guard help train their Chinese counterparts.
Coast Guard ships can travel pretty far south as well. Here, the USCG Cutter Eagle anchors near the Galapagos Islands off the west coast of South America.
Select members of the Coast Guard are also trained to Snuba -- a method of diving similar to Scuba in which the diver breathes air from a tube connected to a ship. Here, a member of the Coast Guard Snubas for the first time off the coast of Honduras.
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