The Ames Tornado of 12 November 2005

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The Ames Tornado of 12 November 2005

I thought we had a pretty good mascot. But when
we showed up at Iowa State and they had a real
tornado, thats the real deal! - CU Buffalo
coach Gary Barnett
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A very interesting event.
Unusually late in the year (but have had 23
tornadoes in November in past 54 years majority
in 2 outbreaks)
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A very interesting event.
Unusually late in the year (but have had 23
tornadoes in November in past 54 years majority
in 2 outbreaks) Almost the feared worst case
scenario with 10,000s of fans arriving at
stadium for ISU Colorado football game
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A very interesting event.
Unusually late in the year (but have had 23
tornadoes in November in past 54 years majority
in 2 outbreaks) Almost the feared worst case
scenario with 10,000s of fans arriving at
stadium for ISU Colorado football game Missed
the stadium by just over 3 miles (to NW), hitting
roughly 50-60 minutes before kickoff
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A very interesting event.
Unusually late in the year (but have had 23
tornadoes in November in past 54 years majority
in 2 outbreaks) Almost the feared worst case
scenario with 10,000s of fans arriving at
stadium for ISU Colorado football game Missed
the stadium by just over 3 miles (to NW), hitting
roughly 50-60 minutes before kickoff Well-forecast
ed (5 days of model runs indicating severe
threat)
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A very interesting event.
Unusually late in the year (but have had 23
tornadoes in November in past 54 years majority
in 2 outbreaks) Almost the feared worst case
scenario with 10,000s of fans arriving at
stadium for ISU Colorado football game Missed
the stadium by just over 3 miles (to NW), hitting
roughly 50-60 minutes before kickoff Well-forecast
ed (5 days of model runs indicating severe
threat) Emergency meeting of police, fire, ISU,
hospital, and city officials at 9 am Saturday
indoor practice facility designated as triage
site, mass casualties expected primarily from
hail and lightning (tornado was considered a
small risk)
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A very interesting event.
Unusually late in the year (but have had 23
tornadoes in November in past 54 years majority
in 2 outbreaks) Almost the feared worst case
scenario with 10,000s of fans arriving at
stadium for ISU Colorado football game Missed
the stadium by just over 3 miles (to NW), hitting
roughly 50-60 minutes before kickoff Well-forecast
ed (5 days of model runs indicating severe
threat) Emergency meeting of police, fire, ISU,
hospital, and city officials at 9 am Saturday
indoor practice facility designated as triage
site, mass casualties expected primarily from
hail and lightning (tornado was considered a
small risk) Planning for disaster about as good
as could be expected, but many WHAT IFs.
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Even with lots of moisture to mix down from
above, the cap looks strong substantial lift
would be needed to remove the cap via cooling
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November 9, 1975
November 15, 1988
500 mb maps from the 2 other big November
events showed a very similar pattern of a strong
short wave swinging into W IA around the time of
the tornado events however, in those events,
the tornadoes occurred in SE EC Iowa
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In the other November events, the 850 mb low was
further to the south, but general pattern was
similar to the 2005 event
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Surface low (approximated here by 925 mb low) and
dew points in prior events also showed best
conditions further southeast than 2005 event.
Lifted Index and SRH maps (not shown) were
typical of cold season tornado outbreaks with
very large SRH and only modest instability. 2005
event was noteworthy in how far NW
tornado-favorable conditions developed, and how
unstable conditions became (LIs of -6 or so
versus -1 or -2 in prior events)
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Saturday. 4pm.2 hrs to kickoff

• SPC still talking mostly squall line
• Tornado warnings in effect in W IA since 319 pm
  (watch since 2 pm) but with no reported touch
  downs
• ISU in frequent communication with NWS-DMX
• Based on storm upstream, ISU prepares to open
  gates to stadium 10 minutes early (420 instead
  of 430)

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2224
2232
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• Just before 430, the first tornadoes touched
  down one near Boxholm in NW Boone county and
  another SW of Woodward in Dallas county
• Woodward tornado seen via live web-cam from
  Madrid (15 miles SW of Ames)

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Near Woodward, IA around 430 CST (R. Pfannkuch)
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2241
2249
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• At 445, tornado reported near Luther (8 miles SW
  of Ames). Unclear if ISU authorities knew this
  but based on sudden wind shift, change in storm
  track, and call to NWS (expressing uncertainty in
  what would happen), officers begin evacuation at
  stadium, urging people to seek shelter in cars
  (for hail/lightning threat scenario 1 in
  morning plan)

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2258
2306
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• At 450, based on tornado reports and knowledge
  of 53 mph movement, evacuations expanded and
  switched to scenario 2 at stadium (tornado
  threat) CU players ordered off field, people
  told to go to concourses, restrooms, nearby
  buildings, ditches
• Tornado touchdown near west edge of Ames at 500
  near Lincoln Way

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Initial touchdown in West Ames
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Near N. Dakota crossing
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Near Deer Run damage
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Entrance to NorthRidge Heights looking NW
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View looking south along G.W.Carver toward Ames
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Twin vortices
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Apparent weak stage of tornado pulls large tree
high into the air
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Looking SSW between Gilbert Ames
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View looking N from Ames Country Club (between
Ames Gilbert)
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View southward of widest part of path just east
of Gilbert (note new Middle School on right)
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Summary

• November 12 2005 tornado event was classic cold
  season situation
• Compared to prior IA November events, tornadic
  conditions extended further NW, and instability
  was greater
• More evidence of enhanced risk when dry line
  reaches Iowa
• Differential diabatic heating may have led to
  enhanced backing in C IA which contributed to
  tornadogenesis importance of sfc boundaries and
  backed winds previously shown in many studies

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What IF?

• Tornado hitting stadium (track 3 miles SE) would
  also have hit Mary Greeley Hospital
• Tornado would have hit stadium by 505 pm, 15
  minutes after tornado evacuation began. Is that
  enough time?
• People in concourses would likely have been blown
  right out, and restrooms were overcrowded
• Metal roofing on nearby buildings would have
  likely caused serious problems to the thousands
  still outside
• Stadium area not equipped for sheltering 50,000
  people
• Track only .5 1 mile NW would have destroyed
  most of town of Gilbert, hitting all 3 schools in
  the district

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Acknowledgments

• Daryl Herzmann, John MacLaughlin
  IEM/photos/helicopter surveys (thanks to those
  who took the photos and videos and contributed
  them, including ISU students)
• Jim Bishop www.stormgasm.com (video)