Tornadoes Brief overview of how tornadoes form, where they are formed, levels of tornadoes, and the damage they can do.

Components for a Tornado Instability of the atmosphere- example: cold, dry air behind a cold front colliding with warm moist air form circulation of low pressure system at the top of a cold front. Wind Shear- wind shear helps in formation for rotating columns of air spinning clockwise and sometimes counter-clockwise. Creates a large cylinder of air spinning horizontally (along the ground). Mesocyclone- Causes development of thunderstorms. In that development comes an updraft of air that circulates as wind shear moves into a vertical position and increases in speed. Wall Cloud- Where tornadoes are produced from a downdraft , also feeds the mesocyclone which strengthens the low pressure under it. The condensation of moisture-rich air drops and forms the wall cloud. Tornado- If the mesocyclone gets strong enough it circulates to the ground with strong winds and kicks up debris making the tornado visible. *Basically how it forms(above) but more deep into the actual tornado part is later*

Where Tornadoes Form and Why Question: Why do you think tornado alley is where it is now based on the maps below and what you have previously learned? (answer in next slide) Tornadoes mostly form in Tornado Alley… here is where all the tornado activity is: But really tornado alley is marked off in the red line: Video-http://dsc.discovery.com/videos/science-of-storm-chasing-tornado-alley-basics.html http://en.wikipedia.org/wiki/Tornado_Alley

Where Tornadoes Form and Why Answer from last slide: As a cold front cuts across the U.S. and through the Great Plains(mostly in the spring and summer) there are several things that happen: The cold front brings cold dry air. The Gulf of Mexico brings in moist air that mixes with the warm air already in the U.S. All these things combine and form thunderstorms. The thunderstorms get the components (as said before) and sometimes form a tornado. *Visual Representation in next slide*

Cold Warm

Where Tornadoes Form Q’s Why do you think there are tornadoes in other places too (eastern USA) when most are in tornado alley? Moisture, cold, and warm air can shift positions based on wind, cold front position, jet stream, etc. 2. How do you think moisture plays a part in forming tornadoes? The moisture-rich air condenses in a thunderstorm and sinks to form a wall cloud where tornadoes usually form. 3. How do you think moisture could reach all the way to Michigan? (look at #1) Again, the moisture could reach farther up from a high pressure system.

The Thunderstorm Formation Red Arrows: Warm Updraft Blue Arrows: Cold front/downdraft Purple Arrows: Air in between White Dots: Hail Formation Rain on left(back) Hail in middle Warm air on right(front)

Further into the Tornado Like before… Question: What are these storm systems called? The updraft of air ( in blue) bends the spinning air moving upwards. Wind shear (in red) makes air spin (in green) The updraft starts rotating with the spinning column of air and could potentially cause tornadoes.

Further into the Tornado Descending air from wall cloud and downdraft in green. Updraft in purple Extra air from updraft and wind shear helping circulation in orange. Can also create tail clouds that also fuel the storms.

Inconceivable Tornado The Fujita Scale http://www.tornadoproject.com/fscale/fscale.htm F-Scale Number Intensity Phrase Wind Speed Type of Damage F0 Gale Tornado 40-72 mph Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages sign boards F1 Moderate Tornado 73-112 mph The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed. F2 Significant Tornado 113-157 mph Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated. F3 Severe Tornado 158-206 mph Roof and some walls torn off well constructed houses; trains overturned; most trees in fore uprooted. F4 Devastating Tornado 207-260 mph Well constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated. F5 Incredible Tornado 261-318 mph Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-inforced concrete structures badly damaged. F6 Inconceivable Tornado 319-379 mph These winds are very unlikely. Missiles, such as cars and refrigerators would do serious secondary damage. If this level is ever achieved, evidence for it might only be found in ground swirl patterns, for it may never be identifiable to engineering studies.

The Enhanced Fujita Scale Question: Why do you think they changed the Fujita Scale? EF-Scale Number Intensity Phrase Wind Speed Type of Damage EF0 Gale Tornado 65-85 mph Light Damage: Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over. EF1 Moderate Tornado 86-110 mph Moderate Damage: Roofs severely stripped; mobile homes overturned or badly damaged; loss of exterior doors; windows and other glass broken. EF2 Significant Tornado 111-135 mph Considerable Damage: Roofs torn off well-constructed houses; foundations of frame homes shifted; mobile homes completely destroyed; large trees snapped or uprooted; light-object missiles generated; cars lifted off ground. EF3 Severe Tornado 136-165 mph Severe Damage: Entire stories of well-constructed houses destroyed; severe damage to large buildings such as shopping malls; trains overturned; trees debarked; heavy cars lifted off the ground and thrown; structures with weak foundations blown away some distance. EF4 Devastating Tornado 166-200 mph Devastating Damage: Whole frame houses and well constructed houses completely leveled; cars thrown and small missiles generated. EF5 Incredible Tornado 200+ mph Incredible Damage: Strong frame houses leveled off foundations and swept away; automobile-sized missiles fly through the air in excess of 100m; high-rise buildings have significant structural deformation; incredible phenomena will occur.

The Enhanced Fujita Scale- Damage Indicators DOD 1 Small Barns or Farm Out buildings 8 2 One-or Two-Family Residences 10 3 Manufactured Home-Single Wide 9 4 Manufactured Homes-Double Wide 12 5 Apartments, Condos, Townhouses (3 or less) 6 Motel 7 Masonry Apartment or Motel Building Small Retail Building (Fast Food Restaurants) Small Professional Building (Doctor’s Office) Strip Mall 11 Large Shopping Mall Large, Isolated Retail Building (K-Mart) 13 Automobile Showroom 14 Automobile Service Building DI# Damage Indicator DOD 15 Elementary School (Single Story) 10 16 Junior or Senior High School 11 17 Low-Rise Buildings (1-4 Stories) 7 18 Mid-Rise Building (5-20 Stories) 19 High-Rise Building (More than 20 Stories) 20 Institutional Building (Hospital) 21 Metal Building System 8 22 Service Station Canopy 6 23 Warehouse Building(Heavy-Timber Construction) 24 Electrical Transmission Lines 25 Free-Standing Towers 3 26 Free-Standing Light Poles, Luminary Poles, Flag Poles 27 Trees: Hardwood 5 28 Trees: Softwood

Fujita/Enhanced Fujita Scale Questions What are the main differences between the Fujita Scale and the Enhanced Fujita Scale? How many indicators of damage are there in the Enhanced Fujita Scale? In the Fujita Scale they have an F6 at 319-379 mph. Why do you think they changed it to an EF5 of 200+ mph? Which Scale do you agree with more? The Fujita or the Enhanced Fujita? Why?(Your Opinion) Took off the F6 tornado and made the wind less per category. 28 Because there were probably only a few tornadoes that had that kind of power(319-379 mph)

Identifying A Tornado Forming(Radar) Questions: Why do you think tornadoes spin counter-clockwise(Hint: coriolis effect)? Also, what is the black dot in the second picture of the two radars(bottom right of radar)? Why do you think a hook forms where a tornado is forming? Tornadoes are found on radar by locating a hook in the storm. Fact: Most tornadoes in supercells form in the southwest part of the storm. Right picture(above) is wind velocity radar.

Identifying A Tornado Forming(Ground) True/False: Supercells spin counter-clockwise like tornadoes. As the wall cloud and mesocyclone get strong enough it can create and tornado and still have that tail cloud to fuel the storm. First, it starts with a tail cloud feeding moisture and spins into the supercell. It starts to form a wall cloud. The wall cloud starts getting bigger and more powerful and producing hail. Tail cloud still there. The tornado can grow stronger from the tail cloud Video-Flashdrive And stronger

Tornado Questions Where do most tornadoes form(what storm system and what part of it)? How does wind shear help a tornado form? What is it called when an updraft of air combines with the wind shear? What is the max amount of wind speed for a tornado according to the Fujita scale? (in mph) 5. What is the lowest stage a tornado could be in the Fujita Scale? (Hint: F__) 6. Name a couple of examples of damage a tornado can do at the stage of F0. 7. How is a tornado spotted on the radar? 8. Can tornadoes come in many shapes and sizes(shapes is only a funnel)? Tornado Alley-Supercells-Wall Cloud It increases wind speed from the updraft in the circulation. Mesocyclone 379 mph F0 Some damage to chimneys; branches broken off trees; push over shallow-rooted trees; damages sign boards. A hook in the storm. Sizes yes, but shapes it can only be a funnel or in some cases a “twisty funnel”

Hail From Dexter Tornado hits the Price’s Car. March 2012

The first three months of 2012 will all have final tornado counts above their respective 10-year averages. We are only at the beginning of the tornado season. Typically the peak months for tornadoes are April, May and June.

January 2012 The first month of the year ended up with 79 tornadoes, which is 243 percent above the 10-year average. This was the third most tornadoes on record in the month of January dating back to 1950. That said, it is far below the record highest total of 212 tornadoes set in January 1999.

February 2012 Below-average amount of significant tornado activity until final two days of the month. An outbreak of tornadoes began in the Plains on February 28 and spread into the Ohio Valley by early February 29. We saw a combined preliminary total of 40 tornadoes during the two days. This outbreak vaulted the tornado count above average for the second month in a row. Overall, the month of February closed out 51 percent above the 10-year average of 35 tornadoes.

March 2012 - 136 Tornados, which is 56 percent above the 10-year March average of 87 tornadoes. - The March 2-3 outbreak produced the large majority of the tornadoes with more than 70 total. The outbreak spawned two EF4 tornadoes - On March 12, a tornado struck near Coleman, Mich. This was the first confirmed tornado north of I-96 in Michigan this early in the season. - A couple of days later, Michigan saw three more tornadoes, including an EF3 in Dexter.