The Coast Guard in Alaska operates in some of the most isolated parts of the US. Here, a Coast Guard vessel gets underway during a winter Bering Sea patrol.
Before taking part in operations, Coast Guard service members must receive substantial training, including in how to rescue people from icy waters.
Crew members of Alaskan Coast Guard ships conduct 100-yard survival swims in 39-degree waters.
Here, a boatswain's mate conducts surface rescue training in Hogg Bay, in Alaska's Prince William Sound.
Coast Guardsmen also receive weapons training. Here, units conduct night-fire exercises with a M-240B machine gun.
US Coast Guard members practice shooting a 50 caliber machine gun at night during a deployment aboard Coast Guard Cutter Stratton.
The Coast Guard must be ready for any scenario in Alaska's unforgiving conditions. Here, a crew trains at recovering oil in ice-strewn water to help prepare for possible spills.
Here, members of the Coast Guard fire and rescue team battle a simulated fire to prepare for an actual aircraft-fire emergency.
The Coast Guard routinely practices for helicopter-evacuation missions at sea, too.
An Air Station Corpus Christi MH-65 Dolphin helicopter lands on Coast Guard Cutter Dauntless November 14, 2013.
And the training is put to good use. Here, an Alaska Coast Guard MH-60 Jayhawk helicopter rescues two crew members from a stranded fishing boat after it ran aground.
Coast Guard members train for rescue in all situations and scenarios. Here, the Coast Guard conducts a maritime helicopter-rescue training session off of Cape Cod.
Rescue training can get pretty intense. Here, a Coast Guard aviation survival technician is 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 the 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 specializes 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 USGC 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 their 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 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 semi-submersible interdicted in international waters off the coast of Central America, 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 Harbor.
In the 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 Harbor, the Coast Guard ensures shipping lanes stay open and protects against any potential acts of terrorism.
A boatcrew from Coast Guard Station Port Canaveral, Florida, enforces a safety and security zone during a rocket launch off the coast of Cape Canaveral, 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 USGC 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.
