Naming the ARkStorm. A California storm is known by the year in which the storm occurred. To equate the storm in a person's mind requires some visceral knowledge of the event, or some understanding of history, meteorology, hydrology, engineering, or other relevant technical discipline. Even with that knowledge, the naming convention does not communicate the magnitude of the event. Therefore, the ARkStorm scenario was named so as to be independent of time, to acknowledge the meteorological phenomena behind most large storms on the U.S. West Coast, namely Atmospheric Rivers (ARs), and to provide some future scale to compare past and future events. The hypothetical scenario would be an Atmospheric River, AR with a value of 1,000 (k), or an ARkStorm. The Multihazards Demonstration Project. The ARkStorm Scenario is the second major project of the U.S. Geological Survey (USGS) Multi-Hazards Demonstration Project (MHDP).