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    "Mothership" Clouds, Other Dangerous Clouds Explained

    By By Meghan Evans, meteorologist
    June 23, 2012, 1:23:46 AM EDT

    Social media helps the rapid exchange of pictures during severe weather outbreaks. The most popular of which are stunning yet sometimes dangerous cloud formations.

    The following is an explanation of "mothership" clouds, "mushroom" clouds and other clouds that should make people react and find safety.


    "Mothership" Clouds, or Supercell Thunderstorms
    Supercell thunderstorms are dangerous storms that have a strong updraft and rotation. These storms can be very long-lived and can produce significant damage in many communities.

    "Storms possessing this structure have been observed to generate the vast majority of long-lived strong and violent (F2-F5) tornadoes, as well as downburst damage and large hail," according to the National Weather Service.

    Supercell thunderstorms often form discretely, or separate from an organized line or cluster of thunderstorms.

    This type of thunderstorm forms in an environment with warm and humid conditions that promote rapid lifting of air. Quickly changing wind speed and/or direction with altitude helps rotation develop by adding a twisting motion to the atmosphere.

    The combination of the discrete formation and strong rotation of supercell thunderstorms allows for a dramatic appearance that can be described as "mothership" clouds.


    Shelf Clouds
    Shelf clouds often form at the leading edge of a gust front or outflow boundary from a thunderstorm, or strong winds flowing down and outward from a storm.

    The outer part of a shelf cloud is often smoother with a notable rising motion exhibited by a tiered look (hence, the name shelf cloud!). Underneath, a turbulent, unsettled appearance is often the case.

    A shelf cloud should be seen as a harbinger of strong winds, so take caution.


    Wall Clouds
    A wall cloud is a cloud that is lowered from a thunderstorm, forming when rapidly rising air causes lower pressure below the storm's main updraft.

    "Wall clouds can range from a fraction of a mile up to nearly five miles in diameter," according to the National Weather Service.

    Wall clouds that rotate are a warning sign of very violent thunderstorms. They can be an indication that a tornado will touch down within minutes or even within an hour.


    Funnel Clouds
    A funnel cloud is a rotating column of air (visible due to condensation) that does not reach the ground.

    If a funnel cloud reaches all the way to the ground then it is classified as a tornado.

    When out on the road, a funnel cloud should be treated as a tornado, since they could touch down.


    A tornado is a rotating column of air, reaching all the way to the ground. Strong tornadoes are one of the most destructive forces of nature on a small scale. The strongest of which can level entire towns.

    A roaring noise, often compared to that of a train, can be heard in many cases when a tornado touches down.

    Tornado Safety Tips
    When A Tornado Destroys Everything

    Vehicles are NOT a safe place to be if there is a tornado nearby.


    Thunderstorm Anvil Clouds
    Anvil clouds are the flat top of a thunderstorm, or cumulonimbus cloud.

    Anvils can spread up to "hundreds of miles downwind from the thunderstorm itself," according to the National Weather Service.

    Lightning can strike from anvil clouds, even far away from a thunderstorm. Lightning described as striking "from out of the blue" is usually from an anvil cloud that has drifted from a thunderstorm.

    Recently, "mushroom" clouds photographed in Beijing were actually anvil clouds.

    Striking mammatus clouds can sometimes be seen below thunderstorm anvil clouds.


    Mammatus Clouds
    The rounded and smooth look of mammutus clouds captivate onlookers. They are often found underneath anvil clouds of severe thunderstorms; however, they can form underneath clouds associated with non-severe thunderstorms as well.

    It takes a turbulent atmosphere for these clouds to develop.


    Asperatus Clouds
    Asperatus clouds are very ominous in appearance, usually described as looking like a rough sea.

    An abundance of heat in the atmosphere is needed to produce enough energy for the dramatic, rolling formations of asperatus clouds. Another factor is the interaction of very moist air (often on the fringes of thunderstorm complexes) with very dry air.

    The darkness of the clouds is likely due to the large amount of water vapor.

    Asperatus clouds are not necessarily accompanied by stormy weather. In fact, they have often been observed without the development of thunderstorms.

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