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
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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.
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Initially members will be expected to stay alerted to TORRO
advisories, watches or discussions using The Forum, where
attention can be focused on periods and areas at risk.
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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.
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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 wxmaps.org. 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.
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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).
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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:
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Checking surface pressure charts and
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By checking high-resolution radar plots covering the place and time in question. This will give a
rough indication of:
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The direction of steering winds and
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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
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Fig 2. Save radar images for that period on that day.
Courtesy ©Netweather radar
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Fig 3. Example synoptic map:
Courtesy ©UKMO
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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.
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Approx maximum track length and width.
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Maximum tornado intensity based on the TORRO intensity scale.
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A graphic overview of the damage track with damage markers Fig 1.
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A radar sequence for that period Fig 2.
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Synoptic map for that day Fig 3.
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Relative station (skew-t) soundings.
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A conclusion.
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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.
