Two U.S. Navy submarines have arrived in the Arctic for regular exercises intended to train crews how to operate in extreme, frigid conditions.
USS Hartford, from Groton, Connecticut, and USS Hampton, from San Diego, will spend five weeks on the mission known as Ice Exercise 2016.
The Los Angeles-class attack submarines arrived this week at U.S. Navy Ice Camp Sargo, a temporary station on a floating ice sheet in the Arctic.
The Navy says the operations help sailors maintain a working knowledge of a region that is different from any other ocean in the world. The Navy is also helping to collect data on changes in the environment.
U.S. Navy submarines have conducted operations under the Arctic ice for more than 50 years.