Cirrus cloud tropopause prevents the warm, moist air forming the thunderstorm from rising any higher, thus creating the flat top. In the tropics, these thunderstorms occasionally produce copious amounts of cirrus from their anvils. High-altitude winds commonly push this dense mat out into an anvil shape that stretches downwind as much as several kilometers. Individual cirrus cloud formations can be the remnants of anvil clouds formed by thunderstorms. In the dissipating stage of a cumulonimbus cloud, when the normal column rising up to the anvil has evaporated or dissipated, the mat of cirrus in the anvil is all that is left. Contrails
Panda Cloud Antivirus Cloud Antivirus relies on its "Collective Intelligence" and the cloud for up-to-date information. It normally uses an Internet connection to access up-to-date information; if the Internet cannot be accessed, it will use a local cache of "the most common threats in circulation". An April 2009 review found Panda Cloud Antivirus 1.0 to be clean, fast, simple, easy to use, and with good detection rates. The same review scored Panda 100.00% in malware detection and 100.0% in malicious URL detection. Its overall score was 100%, a strong protection factor considering it is software. When version 1.0 was released on November 10,