Damage Survey Report for the
November 29, 1998 Payne County Tornado

Summary

On Sunday, November 29, 1998 between approximately 8:00 and 8:20 PM CST, wind damage and a brief, weak tornado (F0) occurred in Payne County just to the west and north of the city of Cushing. Upon receiving reports of damage from the Emergency Manager during the morning of Monday, November 30, a ground survey of the damage was conducted by NWS Norman forecaster Dan Miller. The survey revealed minor wind damage at a rural residence approximately 8 miles west of Cushing and a 2 mile long tornado damage path from 3.5 miles north-northwest of Cushing to 4 miles north of Cushing.

Note: This survey report will concentrate on the tornado damage path.

Map of Damage

Above is a zoomed in map of Payne County with the areas of damage highlighted. Also shown are the locations of four pictures taken during the survey along the tornado damage path. These pictures are described later in the report.

Damage Assessment

For the tornado north of Cushing:

Path length - 2 miles

Path width - 100 yards

F scale rating - F0

Time - approximately 8:10 to 8:15 PM CST

Damage - the damage observed was very minor and was almost exclusively to sheet metal rural buildings with wood frames. In addition, in ALL cases the wind was able to get inside these structures through an open door or a weak link in the construction (see picture 1). Buildings which were well constructed or new experienced little damage. For example, a newly constructed metal frame storage shed at one residence had only the seam between a few joints loosened (see picture 4). A mobile home in the path received structural damage, but was not moved from its original placement on cinder blocks (see picture 2). Other permanent buildings at this site had shingles and shutters blown off (see picture 3). However, two older metal frame structures at the same location were nearly destroyed. There was also noticeable tree damage along the entire path. The most common tree damage observed was broken limbs, but about 10 trees were uprooted.

Picture 1: Looking northeast, this is what remains of a sheet metal, wood frame storage shed attached to the side of a home. The doors on the closest side face south, and according to the owner were found blown inward. The roof is completely gone, with pieces of it found a quarter mile to the northeast. Both of the remaining walls are blown outward slightly. This appears to be a case of classic structural failure where the wind was able to get inside the building through the doors and then blow the building up similar to a balloon with the roof joints failing first.

Picture 2: Looking east, this mobile home was close to the center of the damage path. It received damage to both sides with most windows blown out. The platform and stair in front of the door was also blown away with damage to the door and to the wall/roof joint. However, even though the mobile home was sitting on cement blocks, it was not moved from its original location.

Picture 3: Also looking east, this picture was taken at the same residence as picture 2. This shows the shingles removed from two of the out-buildings.

Picture 4: Looking east-southeast, this picture shows a nearly new sheet metal/wood frame storage building. The building sustained only minor damage on the north facing wall at the wall/roof joint.Two other sheet metal/wood frame structures which were older and much more poorly constructed were destroyed about 50 yards southeast of this location.

Eyewitness Accounts

Persons were at home at three of the residences that received damage at the time of the storm. But, likely due to the fact that all of the people were indoors, and that the event occurred at night, none of them saw a funnel or tornado. Each one said rain accompanied the strong winds and that both the rain and wind began at nearly the same time, but lasted for a very short time. (none could give a definitive answer to specifically how long the wind lasted.)

Comments

This was a rather challenging case to determine whether the damage was caused by downburst (straight line) winds or by a weak, fast moving tornado. Since weak, fast moving tornadoes can leave damage paths which look almost identical to downbursts, other evidence was given considerable weight when making this decision. The conclusion that this was indeed a weak, rapidly moving tornado was based largely on three pieces of evidence which are:

1. The aspect ratio of the damage. A 100 yard wide path is very narrow even for a small downburst, especially when the path length is 2 miles long. Further evidence to support a tornado is seen if one considers the aspect ratio with:

2. The damage path did not broaden. The 100 yard wide path width was very consistent over the entire 2 mile long path. In almost all instances, downburst wind damage paths become wider with time after their beginning point and the damage exhibits divergence. In this case there was evidence of slightly convergent damage which is characteristic of a tornado. And finally,

3. WSR-88D reflectivity and storm relative velocity data indicated a "comma head" bow echo signature with a weak transient circulation embedded in the rain at the time of the event.

After discussion between SOO David Andra, WCM Jim Purpura, Doug Speheger and the surveyor, it was concluded the most of the evidence supported a weak, rapidly moving tornado associated with the comma head of a bow echo embedded in a squall line. Based on the fact that the tornado had ample opportunity to do more severe damage to several structures in its path and did NOT do so, and due to the nature of the construction of the structures it did damage, we concluded that no more than an F0 rating is warranted.

Acknowledgements

The National Weather Service would like to thank the emergency management officials and residents of Payne County, in particular, Oren Jones and Bob Lynch for their assistance during the survey. Also, the surveyor would like to thank David Andra, Jim Purpura and Doug Speheger for their thoughtful comments and assistance in evaluating the data.