U.S. Army Vessel Small Tug Series 911 (Enduring Freedom) pushes through icy waters at Third Port after Winter Storm Grayson on Joint Base Langley-Eustis, Va., Jan. 8, 2018. The storm was classified as a “bomb cyclone,” which is when a storm’s atmospheric pressure falls 24 millibars in 24 hours. Grayson’s pressure fell 53 millibars in 21 hours. (U.S. Air Force photo by Senior Airman Kaylee Dubois)