Low-level clouds are a type of cloud formation that form at altitudes of up to 6, 500 feet. Stratiform clouds, which are also known as strati, are one of the most common types of low-level clouds. They are characterized by their flat, layered appearance and are usually composed of water droplets or ice crystals. Stratiform clouds can be found in all parts of the world and are often seen in the morning or evening when the sun is low in the sky.