Return to Table of Contents This is the unofficial, WWW version of the VORTEX-95 Operations Plan. It may differ from the published operations plan which is available by 15 March from the National Severe Storms Laboratory.
Damage assessment
Since extensive damage surveys are planned for VORTEX, and there will be a number of different measurements of tornadic windflow, VORTEX presents an opportunity to provide an information base by which damage assessment can be " calibrated" (this work is not presently planned by VORTEX investigators, however). That is, the traditional F-scale approach to rating tornadic intensity is the present tool we use for assessing tornado intensity. It has been a topic of considerable debate, because damage assessment after the fact is the convolution of the tornadic winds with the objects in the damage swath. Much of the debate is associated with the rating system, which is keyed to typical frame homes as the baseline for assessment of tornado intensity. The construction details of structures affected by the tornado are typically not known, and the meteorologists who do much of the F-scale rating usually are not familiar with engineering. Moreover, not all tornadoes hit frame homes, and may not hit a frame home when at their peak intensity. There is relatively little information relating other forms of damage (trees being stripped of branches, objects driven into other objects, etc.) to tornadic intensity. Further, the F-scale system attempts to relate estimated windspeeds to the damage. These windspeeds have never been subjected to a systematic validation; they simply are estimates of the windspeeds required to do a given amount of damage and originally were intended to be an extension to the subjective Beaufort windspeed scale.We propose to meld the various windspeed measurements taken during the tornado\qs life cycle with the information from a detailed damage survey. This will provide information about as much of the windfield as we have sampled and analyzed, not just the peak windspeed in the storm. We do not expect to provide answers to all the questions regarding F-scale ratings, but we hope to begin a process of using direct observations of tornadic windspeed to relate to damage observations of all sorts, not just to the standard frame home. It is hoped that this data base will provide useful guidance to interpreting damage in situations where the resources of a field experiment are not available.It is our intent that we provide a range of estimates based on information that may or may not be available in operational damage assessment. This will provide the rating official with some sense of how to use the available input to make an assessment. We also are urging the national F-scale rating data base to include as part of the rating an indication of the method(s) used in arriving at the F-scale rating. Techniques include, but may not be limited to, the following.
Engineering studies
If damage occurs to a structure that was probably designed to certain engineering specifications, such as a business, church, school, etc., we will immediately notify Jim McDonald and/or Richard Peterson at Texas Tech University. If such damage is suspected based on field team observations during intercept work, the FC should be notified, who will notify the Texas Tech researchers.Prior to the beginning of this experiment, letters will be sent to the following groups informing them of the purpose of the experiment, and soliciting their cooperation in the event of a damaging tornado:
If a damaging tornado occurs, the individuals above would be sent a questionnaire, and postage-paid envelope. The questionnaire will seek information regarding debris deposition and the names and phone numbers of others who might have helpful information. Additional questionnaires will be mailed to individuals mentioned in newspaper clippings and other media reports. Other contacts and personal visits will be made as appropriate based on the information gathered through the contacts and mailings.
In addition, a toll-free telephone number will be established and widely publicized so that persons finding debris from a damaging tornado can call and report the nature and location of the debris. Field survey teams, directed by John Snow of OU, will travel into the areas of debris deposition and document all identifiable pieces. Information regarding debris deposition will be synthesized into detailed maps and archived for later research.
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