Hurricanes vs Tornadoes Hurricanes and tornadoes are both

Hurricanes vs Tornadoes!

• Hurricanes and tornadoes are both stormy atmospheric systems that have the potential to cause massive destruction! • They are both caused by instability in atmospheric conditions • However, are they caused by the same types of conditions or different conditions? 2

• Both tropical cyclones and tornadoes are atmospheric vortices, but they have little in common • Tornadoes have diameters on the scale of hundreds of meters and are produced from a single convective storm cloud (i. e. a cumulonimbus cloud). • A tropical cyclone, however, has a diameter on the scale of hundreds of kilometers and is made of many convective storm clouds

• Hurricane - tropical cyclone with sustained winds that exceed 74 mph; accompanied by rain, thunder and lightning • Tornado - rotating column of air that rotates at destructively high speeds, usually accompanied by funnel-shaped downward extension of a cumulonimbus cloud; wind speeds 40 - 110 mph! 4

Let’s think of more differences between tornadoes and hurricanes • Think in terms of: – Wind movement – horizontal and vertical component; for example does the wind have to be moving both horizontally and vertically or just one or the other – Is the storm produced when there is a great temperature gradient (think cold and warm front colliding) or in a stable temperature? – Does it occur primarily over land or water? – Lifetime – measured in days or minutes? – Geographic location

Similarities between tornadoes and hurricanes • Are there similarities between the two types of storms? – Damages – Preparedness • Are there times when a tropical cyclone can cause a tornado? – Can you give some specific examples?

• You are going to work with a partner to make a chart comparing and contrasting hurricanes and tornadoes! • When you are done, we will discuss our findings • Also, each pair should find one example where a hurricane caused a tornado. You can write this example on the bottom of your chart 7

Hurricanes General description Rotation Intensity and scale Location Most affected areas Frequency Characteristics Occurrence Forms of precipitation Temperature gradient Size Shape Life span Amount of warning Effects Tornadoes

Hurricanes Tornadoes General description Cyclone that is located in Rotating column of air N Atlantic or E Pacific; w/winds whirling at high winds > 74 mph speeds usually accompanied by a funnelshaped downward extension of a cumulonimbus cloud; winds 40 – 300 mph Rotation Clockwise in southern hemisphere and counterclockwise in northern Intensity and scale Classified into 5 categories according to Saffir-Simpson Wind Scale; wind speed and intensity of damage increases from 1 -5 Fujita or Enhanced Fujita Scale; classified from 0 – 5, according to wind speeds and intensity of damage/effects Location N Atlanitc, NE Pacific All continents except Antarctica

Hurricanes Tornadoes Most affected areas Caribbean Where there is a convergence of warm and cold fronts – midwest US Frequency 10 - 15 per year 1200 per year in US, Netherlands has highest number of tornadoes per area; most common n spring and even fall Characteristics Heavy winds, floods, storm surge, a lot of rain Strong winds, heavy rain, large hail, strong lightning Occurrence Warm areas Where cold and warm fronts converge, can be anywhere 10

Hurricanes Tornadoes Forms of precipitation Rain, sleet, hail Temperature gradient Small/near zero large Size Diameter of hundreds of kilometer (thousands of times bigger than tornado!) Diameter of hundreds of meters Shape Symmetrical, with often clearly defined center Varies; ; usually cone shaped Life span days minutes Amount of warning Days to weeks; the exact area where the hurricane will hit is known within days, but the storm system will last for longer than that, with changes in its path frequent Minutes to hours! The conditions for the possibility of a tornado can be predicted hours before an event, but tornadoes rarely leave much more thtn a few minutes warning – sometimes none! 11

Effects Hurricanes Tornadoes Vary 12

• Find an example when a hurricane caused a tornado! • • 1967 – hurricane Beulah- 115 in SE Texas! 1985 – Danny 1994 – Beryl 2004 – Hurricane Ivan caused 117 tornadoes! 13

• 2004 – Ivan – most on sept. 17, which developed over a 3 day period in the US, including 37 in VA, 25 in GA 18 in FL, 9 in PA, 8 in AL, 7 in SC, 4 in MD and NC, 3 in WV and 2 in MD • 1980 Hurricane Allen spawned the most damaging tornado - $100 million in damage! • 1964 – Hurricane Hilda produced the deadliest tornado – killing 22 in Louisiana! 14