Strong Winds (typhoons, Hurricanes, Cyclones, Tropical Storms and Tomados)

STRONG WINDS___________________________________________________

(Typhoons, hurricanes, cyclones, tropical storms and tomados)

Mechanism of destruction:-

Pressure and suction from wind pressure, buffeting for hours at a time. Strong wind loads imposed on a structure may cause it to collapse, particularly after many cycles of load reversals. More common damage is building and non-structural elements (roof sheets, cladding, chimneys) blown loose. Wind-borne debris causes damage and injury. High winds cause stormy seas that can sink ships and pound shorelines. Many storms bring heavy rains. Extreme low air pressure at the center of a tornado is very destructive and houses may explode on contact.

Parameters of severity:-

Velocity of wind scales (e.g. Beaufort) gale severity scale Local hurricane/typhoon scales.

Causes:-

Winds generated by pressure differences in weather systems. Strongest winds generated in tropics around severe low pressure systems several hundreds of kilometers diameter (cyclones) known as typhoons in the Pacific and as hurricanes in Americas and elsewhere. Extreme low pressure pockets of much narrower diameter generate rapidly twisting winds in tornados.

Hazard assessment and mapping techniques :-

Meteorological records of wind speeds and direction at weather stations gives probability of high winds in any region. Local factors of topography, vegetation and urbanization may affect microclimate. Past records of cyclone and tornado paths give common patterns of occurrence for damaging wind systems.

Potential for reducing hazard:-

None Cloud seeding may dissipate rain content.

Onset and warning:-

Tornados may strike suddenly but most strong winds build up strength over a number of hours. Low pressure systems and tropical storm development can be detected hours or days