Tornadoes Formation and Characteristics

Tornadoes

• Formation: Tornadoes form when a combination of atmospheric conditions come together, including warm, moist air near the surface, cooler air above, and wind shear.
• Characteristics:
  • Rotating column of air that touches the ground
  • Wind speeds can reach up to 300 mph (480 km/h)
  • Can cause catastrophic damage and loss of life
• Types:
  • Landspout: Weak tornado that forms in weak thunderstorms
  • Waterspout: Tornado that forms over water
  • Supercell: Long-lived thunderstorm that can produce multiple tornadoes

Hurricane Formation

• Formation: Hurricanes form over warm ocean waters (at least 26.5°C) when the atmosphere is unstable and there is low pressure.
• Conditions:
  • Moist air rises, creating convection currents
  • Rotation develops due to Coriolis effect
  • Eye of the storm forms at the center
• Stages:
  1. Tropical disturbance: Initial stage, characterized by thunderstorms and cloudy areas
  2. Tropical depression: Rotating system with sustained winds <39 mph (63 km/h)
  3. Tropical storm: Sustained winds 39-73 mph (63-118 km/h)
  4. Hurricane: Sustained winds >73 mph (118 km/h)

Storm Surge

• Definition: Rise in sea level due to a storm, causing coastal flooding and damage
• Causes:
  • Low atmospheric pressure
  • Strong winds pushing water towards the shore
  • High tides
• Effects:
  • Coastal erosion and flooding
  • Damage to buildings and infrastructure
  • Loss of life

Cyclone Classification

• Tropical cyclones: Rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere
• Classification systems:
  • Saffir-Simpson Hurricane Wind Scale:
    • Category 1: Winds 74-95 mph (119-153 km/h)
    • Category 2: Winds 96-110 mph (154-177 km/h)
    • Category 3: Winds 111-129 mph (178-208 km/h)
    • Category 4: Winds 130-156 mph (209-257 km/h)
    • Category 5: Winds 157 mph or higher (258 km/h or higher)
  • Central Pressure Deficit (CPD): Measures the difference between the central pressure of the cyclone and the surrounding environment

Wind Shear

• Definition: Change in wind speed or direction with height
• Effects on cyclones:
  • Inhibition: High wind shear can disrupt cyclone formation and maintenance
  • Disruption: Wind shear can cause cyclones to weaken or dissipate
• Types:
  • Vertical wind shear: Change in wind speed or direction with height
  • Horizontal wind shear: Change in wind speed or direction over a horizontal distance

Tornadoes

• Form when warm, moist air near the surface meets cooler air above and wind shear
• Characterized by a rotating column of air that touches the ground
• Can have wind speeds up to 300 mph (480 km/h) and cause catastrophic damage and loss of life
• Types include landspouts, weak tornadoes that form in weak thunderstorms
• Waterspouts, tornadoes that form over water
• Supercells, long-lived thunderstorms that can produce multiple tornadoes

Hurricane Formation

• Form over warm ocean waters (at least 26.5°C) when the atmosphere is unstable and there is low pressure
• Moist air rises, creating convection currents, and rotation develops due to the Coriolis effect
• Eye of the storm forms at the center
• Stages include tropical disturbances, initial stage with thunderstorms and cloudy areas
• Tropical depressions, rotating systems with sustained winds of 73 mph (118 km/h)

Storm Surge

• Rise in sea level due to a storm, causing coastal flooding and damage
• Caused by low atmospheric pressure, strong winds pushing water towards the shore, and high tides
• Effects include coastal erosion and flooding, damage to buildings and infrastructure, and loss of life

Cyclone Classification

• Tropical cyclones rotate counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere
• Classified using the Saffir-Simpson Hurricane Wind Scale and Central Pressure Deficit (CPD)
• Saffir-Simpson categories include:
  • Category 1: Winds 74-95 mph (119-153 km/h)
  • Category 2: Winds 96-110 mph (154-177 km/h)
  • Category 3: Winds 111-129 mph (178-208 km/h)
  • Category 4: Winds 130-156 mph (209-257 km/h)
  • Category 5: Winds 157 mph or higher (258 km/h or higher)
• CPD measures the difference between the central pressure of the cyclone and the surrounding environment

Wind Shear

• Change in wind speed or direction with height
• Inhibits cyclone formation and maintenance when high, and disrupts cyclones causing them to weaken or dissipate
• Types include vertical wind shear, change in wind speed or direction with height
• Horizontal wind shear, change in wind speed or direction over a horizontal distance