A unit, in full the 'metre [of] water equivalent', that is an extension of the SI for describing glaciermass in specific units as the thickness of an equal mass having the density of water. 1 kg of liquid water, of density w = 1000 kg m-3, has a vertical extent of exactly 1 mm when distributed uniformly over a horizontal area of 1 m2. More formally, the metre water equivalent (m w. E.) Is obtained by dividing a particular mass per unit area by the density of water:1 m w. E. = 1000 kg m-2 / w . Water equivalents (m w. E.) Can be converted to kg m-2 by multiplying by the density of water, and to ice equivalents (m ice eq.) By multiplying by the density of water and dividing by the density of ice.