The height above the ground or water of the lowest layer of clouds or obscuring phenomena that is reported as "broken," "overcast" or "obscuration" and not classified as "thin" or "partial"
Ilan Kelman (ed.), Vulnerability and Resilience Definitions and References, Version 2, 2007. http://www.islandvulnerability.org/docs/vulnres.pd f, (Vulnr and Resilience - Brit) {524}