Great tornado myth list from Milwaukee NWSFO

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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
230 PM CDT MON APR 18 2005

...TORNADO AND SEVERE WEATHER AWARENESS WEEK IS APRIL 18-22...
...TODAY/S TOPIC IS...PART 2...MOST COMMON TORNADO MYTHS...
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THERE ARE MANY MYTHS CIRCULATING AMONGST SOCIETY ABOUT TORNADOES...
WHICH IN MANY CASES ARE FALSE AND COULD BE LIFE-THREATENING IF
FOLLOWED CLOSELY. SEVERAL OF THESE MYTHS ARE LISTED BELOW ALONG WITH
THE REASONS OF WHY THEY ARE FALSE...

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...WHEN TRAVELING BY CAR...SEEK SHELTER UNDER AN OVER-PASS AS A
TORNADO APPROACHES...

SEEKING SHELTER UNDER AN OVERPASS IS MORE DANGEROUS THAN
STANDING IN AN OPEN FIELD WHILE A TORNADO IS APPROACHING. WHEN A
TORNADO PASSES OVER AN OVERPASS...WINDS ARE FUNNELED UNDER THE
BRIDGE THEREBY INCREASING THE VELOCITY. THE SAME PHENOMENA CAN BE
EXPERIENCED BY STANDING BETWEEN TWO BUILDINGS ON A WINDY DAY.

THE BEST PLACE TO SEEK SHELTER WHILE TRAVELING IS IN A STURDY
BUILDING. IF NO BUILDING IS AVAILABLE...LIE FLAT ON THE GROUND AND
COVER YOUR HEAD. TORNADOES DO NOT FOLLOW TERRAIN EXACTLY...SO CHANCES
ARE IF THE TORNADO COMES DIRECTLY TOWARD YOUR LOCATION...IT WILL PASS
RIGHT OVER YOU. BE WARY HOWEVER...DEBRIS TENDS TO COLLECT IN CULVERTS
AND DITCHES...AND FLASH FLOODING MAY BE POSSIBLE AS WELL.

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...TORNADOES NEVER STRIKE TWICE...

CORDELL KANSAS HAD A TORNADO HIT ON MAY 20TH THREE YEARS IN A
ROW /1916...1917...1918/. IN GUY ARKANSAS...THREE TORNADOES HIT THE
SAME CHURCH ON THE SAME DAY.

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...BIG CITIES AND THEIR TALL BUILDINGS ARE PROTECTED FROM
TORNADOES...

BIG CITIES AND THEIR IMMEDIATE SURROUNDING AREAS ARE NOT
PROTECTED FROM TORNADOES. IN FACT...MANY CITIES ACROSS THE UNITED
STATES HAVE BEEN HIT DIRECTLY WITHIN RECENT TIMES SUCH AS MIAMI...
OKLAHOMA CITY...HOUSTON...FORT WORTH...AND NASHVILLE. EVEN SALT LAKE
CITY HAS BEEN DIRECTLY HIT. UTAH ONLY EXPERIENCES A FEW TORNADOES PER
YEAR...BUT THEY CAN STRIKE ANYWHERE.

SINCE BIG CITIES COVER A RELATIVELY SMALL GEOGRAPHICAL AREA...
THE CHANCES OF A TORNADO STRIKING THAT PARTICULAR AREA ARE RELATIVELY
SMALL...BUT NOT IMPOSSIBLE. THE MYTH THAT TALL BUILDINGS PROTECT
CITIES FROM TORNADOES IS FALSE SINCE TORNADOES ARE TYPICALLY 5 TO 10
MILES IN HEIGHT. A TALL BUILDING OF 500 TO 1000 FEET IN HEIGHT CAN
NOT POSSIBLY DEFLECT OR DESTROY A TORNADO.

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...LARGE LAKES PROTECT NEARBY AREAS FROM TORNADOES...

WHILE COLD WATER AND THE COOL AIR ON TOP OF THE LAKE CAN PROVIDE
FOR A LOCALLY STABLE ENVIRONMENT AT TIMES...CHANCES ARE A
THUNDERSTORM PRODUCING A TORNADO MOVING TOWARD A COLD LAKE HAS
SOMETHING LARGER DRIVING IT THAN THAT COLD WATER CAN INHIBIT.

IN ADDITION...TYPICAL LAKE BREEZES FOUND ALONG THE LAKE MICHIGAN
SHORE ARE OFTEN SHALLOW AND ONLY AFFECT A SMALL PORTION OF THE LOWER
ATMOSPHERE. WARM AND UNSTABLE AIR ABOVE THIS MARINE LAYER/LAKE BREEZE
COULD VERY WELL SUSTAIN A THUNDERSTORM/S STRENGTH. FOR EXAMPLE...ON
MARCH 8 2000...MILWAUKEE COUNTY EXPERIENCED ITS EARLIEST TORNADO ON
RECORD AT A TIME WHEN LAKE MICHIGAN IS CLIMATOLOGICALLY COLDEST.

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...MOUNTAINS...RIDGES...RIVER VALLEYS...AND LARGE LAKES INHIBIT
TORNADO DEVELOPMENT AND/OR SPLIT STORMS...

TORNADOES ARE POSSIBLE IN EVERY CORNER OF THE UNITED STATES...
INCLUDING MOUNTAINS...RIDGES...AND RIVER VALLEYS. WHILE CONDITIONS
AREN/T OPTIMAL FOR TORNADO DEVELOPMENT ON TOP OF MOUNTAINS OR
DIRECTLY OVER LAKE MICHIGAN...TORNADOES HAVE BEEN DOCUMENTED TO CROSS
THE APPALACHIAN MOUNTAINS....GO UP AND DOWN A 10 THOUSAND FOOT TALL
MOUNTAIN IN YELLOWSTONE NATIONAL PARK. STRONG TORNADOES HAVE ALSO
BEEN KNOWN TO CROSS THE MISSISSIPPI RIVER AND OTHER LARGE RIVERS OR
LARGE LAKES.

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...SEEKING SHELTER IN THE SOUTHWEST CORNER OF YOUR HOUSE WILL
PROTECT YOU FROM BEING HIT BY DEBRIS...

THIS MYTH WAS DEVISED SOLELY BY THE MISCONCEPTION THAT ALL
TORNADOES PROPAGATE IN A NORTHEAST DIRECTION. THEREFORE AS THE
TORNADO HITS YOUR HOUSE...ALL THE DEBRIS WILL BE BROUGHT WITH IT TO
THE NORTHEAST AND AWAY FROM YOU. SINCE TORNADOES CAN MOVE FROM ANY
DIRECTION...THIS MYTH IS OBVIOUSLY FALSE.

DEBRIS SUCH AS PICKUP TRUCKS AND CARS CAN ALSO BE SHOVED INTO THE
BASEMENT BY A TORNADO. OBVIOUSLY ONE CAN BE CRUSHED BY A VEHICLE
THAT IS DEPOSITED INTO A BASEMENT. ONE SHOULD POSITION THEMSELVES
UNDER THE I-BEAM OR A HEAVY WORK BENCH TO INCREASE THEIR CHANCES OF
SURVIVAL.

DURING A TORNADO WARNING...PEOPLE WILL WANT TO SEEK SHELTER IN AN
INTERIOR ROOM ON THE LOWEST LEVEL OF THE BUILDING...AWAY FROM
WINDOWS...AND UNDER A STEADY PIECE OF FURNITURE OR STAIRCASE.

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...TO MINIMIZE DAMAGE TO YOUR HOUSE...OPEN ALL THE WINDOWS PRIOR TO
A TORNADO STRIKING IT TO EQUALIZE THE PRESSURE INSIDE AND PREVENT
IT FROM EXPLODING...

WHILE TORNADOES DO HAVE INCREDIBLE PRESSURE CHANGES ASSOCIATED
WITHIN THEM...IF A TORNADO STRIKES YOUR HOUSE DIRECTLY...THE WINDS
ALONE WILL DAMAGE IT SEVERELY ANYWAY. ALL HOMES HAVE THE ABILITY TO
EQUALIZE ITS PRESSURE INSIDE...SINCE NO HOUSE IS 100 PERCENT
COMPLETELY SEALED. FURTHERMORE...BY OPENING WINDOWS YOU ALLOW NO
CHANCE OF THE WINDOW SHIELDING YOU FROM DEBRIS OUTSIDE WHICH MAY
CAUSE BODILY HARM...AND IT WASTES PRECIOUS TIME YOU NEED TO TAKE
COVER.

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...TORNADOES ONLY OCCUR IN THE LATE SPRING AND SUMMER ACROSS
WISCONSIN...

WHILE THE OPTIMAL TIME FOR TORNADO DEVELOPMENT OCCURS DURING MAY
THROUGH JULY ACROSS WISCONSIN...TORNADOES MAY DEVELOP AT ANY TIME OF
DAY AND ON ANY DAY OF THE YEAR. SINCE 1950...TORNADOES HAVE BEEN
DOCUMENTED IN THE BADGER STATE DURING EVERY MONTH OF THE YEAR EXCEPT
FEBRUARY. BECAUSE A FEW TORNADOES HAVE OCCURRED EVEN IN JANUARY...IT
IS NOT IMPOSSIBLE FOR THEM TO DEVELOP IN FEBRUARY....IT/S JUST A
MATTER OF TIME.

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...THE SHAPE AND SIZE OF THE TORNADO DETERMINES HOW STRONG IT IS...

TORNADOES COME IN ALL SHAPES AND SIZES AND ONE SHOULD NOT DEPEND
ON HOW LARGE THEY ARE OR THEIR SHAPE TO DETERMINE STRENGTH. THE ONLY
WAY TO DETERMINE THE STRENGTH OF THE TORNADO IS THROUGH DAMAGE
ASSESSMENTS CONDUCTED BY THE NATIONAL WEATHER SERVICE...OR BY TAKING
A DIRECT MEASUREMENT OF WIND.

DURING DAMAGE ASSESSMENTS...NWS EMPLOYEES LOOK FOR CLUES THAT WILL
TELL THEM HOW STRONG THE WINDS WERE. THE WIND ESTIMATE /OR
MEASUREMENT/ IS THEN RELATED TO THE FUJITA TORNADO SCALE AND A
TORNADO INTENSITY LEVEL WILL BE ASSIGNED.

MERELY BY LOOKING AT THE TORNADO/S SHAPE DOES NOT TELL THE
WHOLE STORY. THE VISIBLE FUNNEL IS CREATED BY CONDENSATION OR DIRT
AND DEBRIS. CONDITIONS THAT CREATE THE VISIBLE FUNNEL WILL CHANGE
EACH TIME A TORNADO DEVELOPS...AND THEREFORE ONE CAN NOT USE THIS
METHOD RELIABLY.

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...SIGNIFICANT PROPERTY OR CROP DAMAGE IS ALWAYS A RESULT OF A
TORNADO...

TORNADOES DO PRODUCE SIGNIFICANT DAMAGE...HOWEVER STRAIGHT-LINE
WINDS CAN BE JUST AS DESTRUCTIVE. DOWN-BURST WINDS ASSOCIATED WITH
SEVERE THUNDERSTORMS ARE CAPABLE OF REACHING WIND SPEEDS OF 100 TO
150 MPH...OR THE EQUIVALENT OF AN F1 OR F2 TORNADO. SIGNIFICANT
DAMAGE DOES NOT ALWAYS IMPLY A TORNADO. SEVERAL...LESS OBVIOUS...
CLUES WILL TELL NWS EMPLOYEES WHETHER A TORNADO OR STRAIGHT-LINE
WINDS CAUSED THE DAMAGE.

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...MOBILE HOMES ATTRACT TORNADOES...

NOTHING ATTRACTS TORNADOES. TORNADOES FORM AND TRAVEL AT THEIR
OWN LEISURE. IT SEEMS AS THOUGH MOBILE HOMES ATTRACT TORNADOES
BECAUSE THEY ARE MORE SUSCEPTIBLE TO DAMAGE. HOWEVER...ON A PRO-
RATED BASIS...HIGHER NUMBERS OF FATALITIES AND INJURIES OCCUR WITH
MOBILE-TRAILER HOMES.

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...THE NUMBER OF TORNADOES PER YEAR HAVE BEEN INCREASING DUE TO MORE
FAVORABLE WEATHER CONDITIONS...

THE NUMBER OF DOCUMENTED TORNADOES IN THE U.S. HAS INCREASED
SINCE THE EARLY 1900S. HOWEVER...THIS INCREASE IS MOSTLY LIKELY DUE
TO THE GENERAL INCREASE IN THE POPULATION...MORE TRAINED STORM
SPOTTERS...BETTER RADAR DETECTION TECHNOLOGY...AND BETTER FOLLOW-UP
DAMAGE SURVEYS. TORNADOES HAVE NOT BECOME MORE COMMON DUE TO MORE
FAVORABLE WEATHER CONDITIONS.

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