Thunderstorms

Thunder N Lightning or Lightning N Thunder

Tornadoes

2/3/11 ► Aim: What are tornados? ► Do Now: Based upon the diagram on the board: A. What type of front is at location L? B. What type of front is at location M? C. Name the possible air masses at P, V, & G. Which air is more dense, air associated with cold or a warm front? This air has a high or low pressure? ► Motivation: Learning of storms that have affect the U.S.

What is a Tornado? ► Definition: ► Violent windstorms that take the form of a rotating funnel of air that extends downward from a cumulonimbus cloud.

What is a Tornado ► They are local storms of short duration usually a few minutes ► Tornadoes have a small diameter usually less than a mile ► Winds can exceed 300mph ► Tornado Tornado

Where and how do they form? ► They generally form in the vicinity of intense cold fronts and squall lines (moving lines of thunderstorms). ► Central US, called Tornado Alley, a year. ► In the spring cP air from the north is still very cold and dry, and mT air from the south is warm, humid and unstable. When these two air-masses meet, tornadoes are spawn.

Hail Storm

September 16, 2010 Winds Up to 70mph

Songer

Tornado Formation

Where Tornados Occur Tornado Alley covers the Great Plains states

Tornado Facts ► Duration: a few minutes ► Diameter (Avg.): 0.4 km ► Length of path (Avg.): 6 km ► Funnel can travel from 1 mph up to 70 mph, usually travels at 30 mph ► Texas is #1 for frequency of tornados per year ► Between 1950 and 1995 Texas had 5,722 recorded tornados ► Risk of death in a tornado in Texas: 1 in 1,054,267

Tornado Myths ► A highway overpass is a safe place to take shelter under during a tornado ► Overpass Overpass

Dust Devil/ Water Sprout

Fujita Scale

Fugita Scale

F0 Category ► (Weak) winds (40-72) mph, little damage ► Damage: tree branches snapped, chimneys toppled, signs torn down

F3 Category ► (Strong) winds: ( ) mph, severe damage ► Damage: most trees uprooted, trains overturned, roofs torn off, walls demolished

Tornado Path width and length of the tornado path

F5 Oklahoma 1999

F5 Category ► (Violent) winds: ( ) mph, incredible damage; rare Damage: bark peeled off trees, houses lifted off foundations, vehicles travel greater than 100 m through the air

Tornado Occurrence by Category

Tornado Deaths by Category

The Tornado Outbreak of May 3, 1999 ► Severe thunderstorms move into Ok, TX, Ks and spawn estimated 70 tornados, most occurred in Oklahoma ► In Oklahoma 40 people killed, 675 injured ► Damage: $1.2 billion ► Largest tornado outbreak in Oklahoma history ► 1,780 homes completely destroyed ► 6,550 homes damaged

Waterspouts A waterspout is a tornado that forms over a body of water, or a tornado that moves from land onto water A waterspout is a tornado that forms over a body of water, or a tornado that moves from land onto water

Tornado Hazards ► Violent Winds ► Flying Debris, cause for most deaths and injuries ► Tornadoes have driven a piece of straw through a wooden plank, uproot trees, pick up cars, buses, and trains

Mammatus clouds Mammatus clouds Green sky Green sky

Tornado Damage Tornados mainly cause damage by picking up something and throwing it through the air or hurling objects against something Tornados mainly cause damage by picking up something and throwing it through the air or hurling objects against something A 20-ton trailer blown off U.S. 30; it bounced 5 times A pick-up truck caught in the path of a tornado

Tornado Safety ► In Homes or Buildings- go to basement, or interior room such as bathroom, closet, etc. ► In Cars or Mobile Homes- abandon them Immediately. ► If in an open field- lie flat in the nearest ditch or depression and use hands to cover head.

Tornado History ► The “Tri-State Tornado” is the most violent tornado on record ► On March 18, 1925, the tornado formed in Missouri and traveled 219 miles across Illinois into Indiana ► The funnel was up to.75 miles across and traveled as fast as 73 mph. ► It killed approximately 635 people