Cirrus, Stratus, Cumulus and Cumulonimbus Types of Clouds Cirrus, Stratus, Cumulus and Cumulonimbus

What causes clouds to form? There must be three main ingredients present in order for clouds to form: 1. Moisture - There must be sufficient water vapor in the air to build a cloud. 2. Cooling air - The air temperature must decrease enough for water vapor to condense and form droplets. 3. Condensation nuclei - Tiny particles, invisible to the human eye, such as dust, dirt, and pollutants, provide surfaces on which water molecules can gather and condense into water droplets. If the conditions are right, then a cloud will form. Clouds often form where two weather fronts meet, like when a cold front meets a warm front. The kind of clouds that form can say a lot about what type of weather is coming! The main kinds of clouds are stratus, cumulus, and cirrus clouds, and each one forms under different conditions.

Cirrus Clouds Cirrus is a Latin word that means “curl of hair”. Typically found at high altitudes. Thin wispy clouds Cirrus clouds are composed of ice crystals that originate from the freezing of super cooled water droplets. Cirrus generally occur in fair weather and point in the direction of air movement at their elevation.

Stratus Clouds The word stratus comes from Latin, means “to spread out”. Stratus clouds are usually low clouds seen on an overcast day. Stratus clouds often block out the sun. Usually produce light to heavy continuous rain. Fog can be considered a low stratus cloud in contact with the ground. When the fog lifts, it usually becomes true stratus.

Cumulus Clouds The word cumulus comes from Latin, “means heap or pile”. Cumulus clouds are usually puffy with distinct edges and usually a noticeable vertical (upward) development. Cumulus clouds are sometimes associated with thunderstorms.

Cumulonimbus Clouds These clouds are named because they are puffy ("cumulo") and because they often are dark clouds which cause rainstorms ("nimbus"). Cumulonimbus clouds are different because they cannot be classified as low, middle or high altitude clouds. These are often storm clouds which can be ten or more miles in height, extending through all the levels of altitude. These clouds form when a front of cool air meets a body of hot, moist air. Cumulonimbus clouds can produce rain showers, snow showers, hail, or even thunderstorms

Cumulonimbus