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.
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.
|Tornado north of Dunkerton
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.
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.)
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.
|The compass direction to which the tops of the trees are pointing:
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.