Restricted Visibility : Under maritime rules means any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms, or other similar causes
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}