Cyclones (Tropical) – Associated Hazards


Tropical storms and hurricanes are dangerous storms with a series of hazards that can have an impact long after the winds die down. While most people know that tropical cyclones can contain damaging wind, many do not realize that they also produce several other hazards, both directly and indirectly.

Here’s a look at tropical storm and hurricane-related hazards and how you can help protect your family and property against them: [1]

Storm surge is simply water that is pushed toward the shore by the force of the winds swirling around the storm. This advancing surge combines with the normal tides to create the hurricane storm tide, which can increase the average water level 15 feet (4.5 m) or more.

In addition, wind driven waves are superimposed on the storm tide. This rise in water level can cause severe flooding in coastal areas, particularly when the storm tide coincides with the normal high tides. Because much of the United States' densely populated Atlantic and Gulf Coast coastlines lie less than 10 feet above mean sea level, the danger from storm tides is tremendous.

The level of surge in a particular area is also determined by the slope of the continental shelf. A shallow slope off the coast will allow a greater surge to inundate coastal communities. Communities with a steeper continental shelf will not see as much surge inundation, although large breaking waves can still present major problems. Storm tides, waves, and currents in confined harbors severely damage ships, marinas, and pleasure boats.

High Tide, Storm Surge, and Storm Tide[2]
Wind Damage[3]

Hurricanes are known for their damaging winds. They are rated in strength by their wind also. However, when the NWS's National Hurricane Center issues a statement concerning the wind and category, that value is for sustained wind only. This hurricane scale does not include gusts or squalls.

Gusts are short but rapid bursts in wind speed and are primarily caused by turbulence over land mixing faster air aloft to the surface. Squalls, on the other hand, are longer periods of increased wind speeds and are generally associated with the bands of thunderstorms which make-up the spiral bands around the hurricane.

A tropical cyclone's wind damages and destroys structures two ways. First, many homes are damaged or destroyed when the high wind simply lifts the roof off of the dwellings. The process involved is called Bernoulli's Principle which implies the faster the air moves the lower the pressure within the air becomes. The high wind moving over the top of the roof creates lower pressure on the exposed side of the roof relative to the attic side.

The second way the wind destroys buildings can also be a result of the roof becoming airborne. The wind picks up the debris (i.e. wood, metal siding, toys, trash cans, tree branches, etc.) and sends them hurling at high speeds into other structures.

Inland Flooding[4]

In addition to the storm surge and high winds, tropical cyclones threaten the United States with their torrential rains and flooding. Even after the wind has diminished, the flooding potential of these storms remains for several days.

It is common to think the stronger the storm the greater the potential for flooding. However, this is not always the case. A weak, slow moving tropical storm can cause more damage due to flooding than a more powerful fast moving hurricane.

High Probability of Tornadoes Area[4]

Tropical cyclones can also produce tornadoes that add to the storm's destructive power. Tornadoes are most likely to occur in the right-front quadrant of the hurricane relative to its motion. However, they are also often found elsewhere embedded in the rainbands, well away from the center of the tropical cyclones.

Some tropical cyclones seem to produce no tornadoes, while others develop multiple ones. Studies have shown that more than half of the landfalling hurricanes produce at least one tornado. When associated with hurricanes, tornadoes are not usually accompanied by hail or a lot of lightning.

A tornado watch is usually issued when a tropical cyclone is about to move onshore. The watch box is generally to the right of the tropical cyclone's path.


Infographic courtesy of The Allstate Blog.


  1. NOAA – NWS – JetStream – Online School for Weather – Tropical Cyclone Hazards:
  2. Image Source: [Accessed March 14, 2014]
  3. Image Source: [Accessed March 14, 2014]
  4. Image Source: [Accessed March 14, 2014]
  5. Image Source: [Accessed March 14, 2014]


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