WATER SPOUT AND DUST TORNADOES (What is it all about?):


  1. Definitions of Water Spout and Dust Tornadoes
  2. Types of Water Spout
  3. Stages Formation/Formation of Water Spout and Dust Devil


                                         1. Definitions of Water Spout and Dust Tornadoes

WATER SPOUT- is a rotating column of water and spray formed by a whirlwind occurring over the sea or other body of water.

-it is also called rain spout, a pipe running down the side of a house or other building to carry away water from the gutter of the roof.
– a spout, duct, or the like, from which water is discharged.
-a funnel-shaped or tubular portion of a cloud over the ocean or other body of water that, laden with mist and spray, resembles a solid column of water reaching upward to the cloud from which it hangs.

– is an intense columnar vortex (usually appearing as a funnel-shaped cloud) that occurs over a body of water. They are connected to a towering cumuliform cloud or a cumulonimbos cloud.

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DUST  TORNADOES-also known as dust devil is a strong  well-formed, and relatively long-lived whirlwind, ranging from small (half a meter wide and a few meters tall) to large (more than 10 meters wide and more than 1000 meters tall).

– it is usually harmless, but can on rare occasions grow large to pose a threat to both people and property

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-dust tornadoes are comparable to dust devil which both are weather phenomenon of a  vertically oriented rotating column of wind.

2. Types of Water Spout

  • Non-Tornadic– waterspouts that are not associated with a rotating updraft of a super cell thunderstorm. It occurs in coastal waters and are associated with dark, flat-bottomed, developing convective cumulus towers.
  • Tornadic- are formed from mesocyclonic action in a manner essentially identical to traditional land-based tornadoes in connection with severe thunder storms, but simply occurring over water,which travels from land to a body of water.
  • Snow spout-  also known as snow devil, ice spout, or snownado a waterspout forming under the base of a snow squall.



Stages Formation/Formation of Water Spout and Dust Tornadoes

Formation of Water Spout- Waterspouts exist on a micro scale, where their environment is less than two kilometers in width. The cloud from which they develop can be as innocuous as a moderate cumulus, or as great as a super cell. While some waterspouts are strong and tornadic in nature, most are much weaker and caused by different atmospheric dynamics. They normally develop in moisture-laden environments as their parent clouds are in the process of development, and it is theorized they spin as they move up the surface boundary from the horizontal shear near the surface, and then stretch upwards to the cloud once the low level shear vortex aligns with a developing cumulus cloud or thunderstorm.

      Stages Of Water Spout Formation:

1. Dark spot the surface of the water takes on a dark appearance where the vortex or column of rotating wind reaches it.

2. Spiral pattern- light and dark bands spiral out from the dark spot.

3. Spray ring- a swirling ring of sea spray called a cascade forms around the dark spot. It appears to have an eye at the center, similar to that seen in a hurricane.

4. Mature vortexthe waterspout is now at its most intense stage, visible from the surface of the water to the clouds overhead. It appears to have a hollow funnel and may be surrounded by vapor.

 5. Decay- when the flow of warm air into the vortex weakens, the waterspout collapses.
 Formation of Dust Tornadoes- a dust devil, fully formed, is a funnel-like chimney through which hot air moves, both upwards and in a circle. As the hot air rises, it cools, loses its buoyancy and eventually ceases to rise. As it rises, it displaces air which descends outside the core of the vortex. This cool air returning acts as a balance against the spinning hot-air outer wall and keeps the system stable.
         Dust Devil Formation:
  • Flat barren terrain, desert or tarmac flat conditions increase the likelihood of the hot-air “fuel” being a near constant. Dusty or sandy conditions will cause particles to become caught up in the vortex, making the dust devil easily visible.
  • Clear skies or lightly cloudy conditions- the surface needs to absorb significant amounts of solar energy to heat the air near the surface and create ideal dust devil conditions.
  • Light or no wind and cool atmospheric temperature- the underlying factor for sustainability of a dust devil is the extreme difference in temperature between the near-surface air and the atmosphere. Windy conditions will destabilize the spinning effect (like a tornado) of a dust devil.





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