Fog forms around Pittsburghs cityscape after the snow and ice melt on the surrounding rivers Jan. 25, 2024.The U.S. Army Corps of Engineers Pittsburgh District operates 23 navigable locks and dams on the Allegheny, Monongahela and Ohio rivers year-round regardless of weather, including in foggy conditions that restrict visibility. Many towboat crews continue working on the rivers even in the fog, sometimes staging their barges along various parts along Pittsburghs waterways as they wait for the mist to lift. Regardless of weather, the Pittsburgh Districts locks and dams remain open for traffic, ready whenever navigation needs to pass commodities through their chambers.The district is responsible for keeping navigation flowing through Pittsburgh, known as the Headwaters District, to and from the rest of the nation. Transporting commodities on the waterways is four times less expensive than by trucks and 33 percent cheaper than by rail.