Beginning near Aplington, the tornado devastated Parkersburg and
continued through New Hartford, cut a path north of Cedar
Falls/Waterloo, then headed down Dunkerton Road toward Dunkerton.
Between 3 and 4 miles west of Dunkerton the tornado turned
northeast, missing the town, and continued across the countryside
south of Fairbank toward Hazelton.
The EF5 tornado finally dissipated near Stanley, having cut a
path of destruction across 43 miles of Iowa landscape and leaving 8
dead in its wake. National Weather Service reports estimate the
tornado was at its widest as it traveled north of Dunkerton.
See
WCF Courier interactive tornado map.
|
| Tornado north of
Dunkerton |
As of the posting of this cache there have been two EF5 tornadoes
recorded since the Enhanced Fujita Scale was introduced on February
1, 2007, the most recent one being the one that hit
Parkersburg
on May 25, 2008. See
Greensburg, Kansas tornado, and
Late-May 2008 tornado outbreak sequence.
The Enhanced Fujita Scale, or EF Scale, is the scale for rating
the strength of tornadoes in the United States estimated via the
damage they cause. The Enhanced Fujita Scale ratings are:
- EF0. Light damage. Wind 65 to 85 mph.
Peels surface off some roofs; some damage to gutters or siding;
branches broken off trees; shallow-rooted trees pushed over.
- EF1. Moderate damage. Wind 86 to 110 mph.
Roofs severely stripped; mobile homes overturned or badly damaged;
loss of exterior doors; windows and other glass broken.
- EF2. Considerable damage. Wind 111 to 135 mph.
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 damage Wind 136 to 165 mph.
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 damage. Wind 166 to 200 mph.
Well-constructed houses and whole frame houses completely leveled;
cars thrown and small missiles generated.
- EF5. Total destruction. Wind above 200 mph.
Strong frame houses leveled off foundations and swept away;
automobile-sized missiles fly through the air in excess of 100 m
(109 yd); steel reinforced concrete structure badly damaged;
high-rise buildings have significant structural deformation;
incredible phenomena will occur.
Cache coordinates:
N 42 35.ABC
W 092 14.0D
To find the cache coordinates answer the following questions and
use the values determined to fill in the missing numbers in the
coordinates.
(Photos taken by
Iowa Helicopter Survey)
1. The aerial photo above was taken of the farm just
south of the Crane Creek bridge the day after the tornado. The
house still stands but the barn, a pole building, and other out
buildings have been flattened. Based on the evidence in this photo
and from the Enhanced Fujita Scale information given above, what EF
damage rating is appropriate for the damage to this farm? (Click
the photo for a close up view.) Use the EF scale number as x in the
formula below to determine the value for A.
A = x + 6 Hint: Tornadoes vary in intensity regardless of
shape, size, and location.
2. The tornado traveled almost straight east along
Dunkerton Road from north of Cedar Falls. Before it reached the E.
Dunkerton Road/N. Raymond Road intersection the tornado started to
veer to the north. By the time it crossed N. Raymond Road at Crane
Creek, it was traveling in a northeasterly direction. Based on your
observations at the site and from the aerial photo above, in what
direction are the majority of the trees at Crane Creek lying? What
does this tell you about the winds within the tornado? (Click the
photo for a close up view.)
| The compass direction to which the tops of the trees are
pointing: |
___ |
___ |
|
B |
C |
Use the conversion scale N=2, S=6, E=5, W=9 and convert your
compass direction above to two numbers to use as BC in the
coordinates.
3. The aerial photo above shows the scoured ground and
debris as the tornado traveled east of the cache location. As a
reference point, the trees along Crane Creek appear at the top of
the photo. (Click the photo for a close up view.) The tornado was
approximately as wide as the north and south waypoints listed
below. Travel to each waypoint and record the distance. How wide
was the tornado when it crossed N. Raymond Road? Use this number as
y (rounded to the nearest 10th) in the formula below to determine D
in the coordinates.
D = y miles + 39.8
Note: As you go, notice the new construction on your left and
right. Every house and building between the waypoints suffered some
damage or was completely destroyed by the tornado.
You can check your answers for this puzzle on
Geochecker.com.
Got it? Now, you'll want to drive to the final location.
The cache container is a small metal box covered in camo duct tape.
Original contents include a brand new, special voice-recording
Travel Bug "Calling All GeoCachers!" with a special message to the
FTF, a log, and pencil. There's room for a few small trinkets for
trading.