The Tornado Damage Site Investigator
TORRO's most productive area of research involves members conducting tornado damage site investigations. Our aims are:-
- To establish that it was in fact a tornadic event.
- To assist with media enquiries at the scene.
- To take photographic and other essential evidence of associated damage.
- To obtain statements from eyewitnesses in order to realize the facts.
- To write research papers for the Journal of Meteorology.
- To add the event to TORRO's ongoing severe weather database.
- To research and log such events that would otherwise go unrecorded.
A vast team of scientists, researchers, and enthusiasts carry out various activities to support the SI (site investigation). These range from obtaining satellite images, synoptic charts, media information and reports to providing maps and live assistance to the investigator. It is hoped that by directly involving its members in such activities they will learn more about the tornado as an entity capable of causing devastating consequences. Visiting damage sites gives a personal realization to 'cause and consequence'. The 'text book' interpretation is limited and it is only by way of personal involvement that we can truly hope to achieve an understanding. Media will often report a small area of obvious damage and entirely miss the 20 or so uprooted trees a mile or so further on. Such damage paths will often cover a much broader area than is initially indicated. Only by meticulous painstaking research can we hope to establish the facts and accurately catalogue the incident.
TORRO has a database of members willing to undertake such work. Our network of potential site investigators spans the furthest reaches of the UK, Scotland, Wales and Ireland. Initially members are alerted to the risk via the TORRO forum discussions and advisories. TORRO also has good links with the Meteorological Office and is grateful for the many hundreds of reports that are delivered to us. It is not unusual for an investigator local to such an event to attend the scene well before the press has arrived, sometimes within an hour or so.
Below is a set of guidelines but please keep in mind that site investigators do not need all the know-how or understanding of the technical or meteorological sections of an investigation. The only requirement is willingness and a desire to learn because there are no academics of this phenomenon, only differing levels of experience.
Guidelines to Achieving Successful Tornado Damage Site Investigations- All investigators are expected to behave in a responsible and courteous manner. It is possible that 'persons' could be injured or have lost part of their house or other belongings. Investigators are also reminded that they undertake investigations at their own risk and that TORRO cannot be held responsible for any loss or damage associated with their individual research.
- Initially members will be expected to stay alerted to TORRO advisories, watches or discussions using the forum (if you are not registered on the forum then please go to http://www.torro.org.uk/forum/ category-view.asp), where attention can be focused on periods and areas at risk.
- Tornado reports are then forwarded to the nearest member to that location with as much information as is available. If the exact location is not known then investigators may have to contact their local emergency services or press for more information. This requires a willing 'hands on' approach.
- Attending the site as soon as is practicable is essential though a partial site investigation will often reveal some worthy information days, if not weeks later. Please remember to take the necessary kit (bottom of page) with you in order to achieve the best results.
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Investigators should realistically place themselves somewhere
on the damage track and draw a line on a map which coincides with
the mid level steering winds for that day* (See Footnote). An
example of 500mb streamlines can be found at pages.unibas.ch/geo/mcr/3d/meteo/dt/index.htm. This
will 'commonly' show orientation from somewhere between West to
South and North to East on a compass, though there are sometimes
exceptions to this rule (check this before you leave). By
extending this line in each direction from where you are standing
we might often see that it will cross roads or footpaths at
certain points. Use these visual intersections to find further
damage. Add this detail to your map. Ideally it is best to find
the point of touch down first and then walk the entire length on
foot, noting all damage as in 'Fig 1' below.
* indicates that the nearest (skew.t) sounding results will be a more reliable source when submitting the report.
- On scene, endeavour to note the type of damage, movement direction of projectiles and fall direction of snapped or uprooted trees, from the touchdown point to where the tornado finally lost contact with the ground. This is simply done in most cases by following the visible damage up-track from the intercept-point and then down-track. If it was a tornado, there will usually be telltale signatures: in particular a surgical and narrow damage-path is common, along which there is devastation but away from which there is little sign of damage; in addition look for the cyclonic lay of trees and projectiles (i.e. looking down-track, a de branched tree will have its branches thrown to the left, at right-angles to the tornado track).
- Map the damage in detail. In some cases, a tornado may lift and touch down again repeatedly resulting in a more fragmented trail of damage. In order to prepare for this possibility, it is recommended that the weather at the time be checked prior to setting out for the site. This may be done by:
- Checking surface pressure charts and
- By checking high-resolution radar plots covering the place and time in question. This will give a rough indication of:
- The direction of steering winds and
- The track of the storm, giving a broad linear zone that can be repeatedly traversed throughout, wherever possible along the track to check for signs of damage. This zone needs to be about 2km in width in order to allow for the deviation from the synoptic flow exhibited by some tornadoes.
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Fig 1. (Farnborough Tornado Track December 2006)
Courtesy ©Google Earth -
Fig 2. Save radar images for that period on that day.
Courtesy ©Netweather radar -
Fig 3. Example synoptic map:
Courtesy ©UKMO
- A reliable source of information will come from eyewitnesses or people who have suffered damage to their homes. It may be necessary to knock a few doors. Damage tracks will often pass over private land so please get permission from the owner whenever possible. Take photographs of damage, paying particular attention to unusual damage events. This will all go toward evidence to base your final conclusion.
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A basic investigation should at the very least contain the following detail:
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- Day, date, time and place.
- Approx maximum track length and width.
- Maximum tornado intensity based on the TORRO intensity scale.
- A graphic overview of the damage track with damage markers Fig 1.
- A radar sequence for that period Fig 2.
- Synoptic map for that day Fig 3.
- Relative station (skew-t) soundings.
- A conclusion.
- Post your full report directly to correct thread on the TORRO forum.
If you would like to be a tornado damage site investigator please complete the
application form below.
Important: You must be a member of or affiliated with TORRO to be able to
act in an official capacity for the Organisation. We regret that applications without a recognised membership
number can not be considered.
Please print off our Tornado Site Investigation
Check List.
Compare site damage with the International Tornado Intensity Scale.