Building Phenomenal Seas: The Rapid Intensification of the Extratropical Hurricane-Force Low of January 2–6, 2018

Each year, nearly $2 trillion worth of imports and exports are transported through U.S. seaports aboard 60,000 ocean-faring vessels. Additionally, over 11 million Americans board cruise ships annually from U.S. seaports. Marine hazards such as strong winds and large waves threaten life and property at sea. In particular, extratropical lows of hurricane-force intensity generate severe winds and extreme waves that greatly increase the danger at sea. Since 2006, the Ocean Prediction Center (OPC) has analyzed approximately 45 hurricane-force wind events annually over the North Atlantic Ocean. These storms can be quite large, fast moving, and produce impactful wind and wave conditions across the shipping routes.

The rapidly deepening hurricane-force low of January 2-6, 2018 is presented as an example of how these storms rapidly produce phenomenal sea heights and present an extreme danger to life and property at sea. The process of wave growth is driven by wind speed, fetch, and duration. The process of dynamic fetch allows the fetch region to stay constant as the storm moves, increasing the duration in which extreme winds can act on the ocean waves produced by the storm. Through dynamic fetch, the hurricane-force low of January 2-6, 2018 was able build phenomenal seas in excess of 14 meters in the southeast quadrant of the storm.