Low cloudsLow clouds0–2 kmLow clouds usually have bases below 2 km. Stratus forms a grey layer, stratocumulus makes broad rolls, and cumulus grows upward. Cumulonimbus can tower through much of the troposphere.StratocumulusLow rounded cloud masses joined into patches, rolls or a broad layer.CumulusClouds with flat bases and rounded tops, formed by rising buoyant air.CumulonimbusA deep thunderstorm cloud with a low base and a high, often anvil-shaped top. It can produce heavy rain, lightning and hail.StratusA low, fairly uniform cloud layer that may produce drizzle.Clouds of the troposphereHigh cloudsMiddle cloudsLow cloudsCoast & mountainsCirrusCirrocumulusCirrostratusAltocumulusAltostratusNimbostratusStratocumulusCumulusCumulonimbusStratusCloud classification · WMOTroposphere
