Voluntary Damage Surveys by Sam Barricklow - K5KJ
I occasionally
perform damage surveys and submit them to the NWSFO Warning and Preparedness Officer at the NWS office in Fort Worth. I typically, but not always, pick events that the NWS
cannot do themselves. Data from my reports are often included in the
official storm report.
As far as training is concerned, the NWS does not currently offer
training for non-government personnel. You can get damage assessment
training through the Red Cross, your local SKYWARN or ARES group, or other emergency relief organizations,
but their focus may not be the same as that of the NWS. My "training" came
from many years of reading NWS damage surveys, training materials and
studying tornado and downburst debris on my own after events and discussing events with NWS personnel.
The major events will likely be handled by NWS personnel. It's the
relatively minor or remote events that may require your services. After
an outbreak, the smaller or less significant tornadoes, wind or flood events may not warrant the attention of the NWS (due to their limited resources
they must select the most significant events). You should always coordinate
your activities with your local NWS or your local civil defense officials
beforehand.
You can perform your own independent survey without any "official"
approval. But, the local police may not appreciate your interest and they may be suspicious of your intentions. Don't misunderstand, I have not always
coordinated my own surveys with anyone else and have sometimes performed
surveys only to satisfy my own curiosity. I DO always offer my
surveys to the NWS for inclusion in storm data.
If you do perform damage surveys, you must be thorough. Storm Data
reports are sometimes used in court to settle insurance claims. You
will need to allocate yourself plenty of time. You should also coordinate your
efforts with your local NWS in advance and understand that you are doing
the survey at your own risk. If you are questioned by the local
authorities, you may need a name and a phone number at the NWS for them
to confirm your purpose for being there.
This is not a job for thrill seekers or the faint of heart. You must
take into account the feelings of people who were affected by the event. You must exhibit a professional attitude when performing damage
surveys. You may also come across some horrible things during your
survey, especially if you perform a survey quickly after an event.
As far as the technical aspects of performing the survey, you must be
prepared when you enter the affected area. Items you will need include:
- your RACES, SKYWARN, ARES or other identification along with the issuing organization's approval to be there (If you don't have express approval from one of
these organizations, don't use them as your reason for being there. Doing so could get you expelled from the organization.) Other items you will need includes:
- an accurate and detailed map
- a fully charged cell phone
- a camera (still and/or video)
- a notepad and/or tape recorder to log damage information
- a copy of the Fujita damage scale with photo examples for reference
- a GPS receiver for remote or poorly marked roads
- binoculars or a spotting scope to view damage that is inaccessible
- enough gasoline, food and water for your own needs
- steel toe, steel shank boots if you plan to walk through the area
- a small first aid kit for cuts and scrapes
- up to date vaccination for tetanus
If you plan to try to determine whether an event was caused by a tornado
or downburst, you must have some understanding of how the two events
differ. Remember to associate tornadoes with convergence and downbursts
with divergence. In other words, air flows toward tornadoes and away
from downbursts. Whenever possible, record where debris originated and where it came to rest.
Eastward or northeastward moving tornadoes usually produce higher wind
speeds on their south and southeast flanks, due in part to the addition
of their forward motion with the speed that the winds circulating around
the center. But, generally speaking, look for evidence of converging
winds. In populated areas, TV antennas, small trees and wooden fences
along the edges of the damage path provide good evidence for wind
direction (convergence or divergence). Twisted trees or signs don't
necessarily indicate tornado damage. High straight line winds can also
twist trees, signs and other objects, depending on the direction of the
wind relative to the shape and resistance of the object. Tornadoes will
often "sandblast" objects, imbedding dirt, sand, broken glass and other
small debris into objects. I've not seen straight line winds produce
this effect. Tornadoes produce a path of damage that may be relatively
narrow and usually more confined compared to a downburst. The
damage is often more consistent over a longer path than that produced by
a downburst.
Downbursts typically fan out in the direction of wind flow, diverging
from the "point" where they first impact the ground. Downburst damage
is typically most intense near where it first impacts the ground, becoming progressively less intense as you move away
from the point of origin.
Also be aware that multiple downbursts may occur in association with a
tornado, producing a confusing mixture of tornado and downburst damage. This is often the case near the beginning and end of a tornado's life. Significant downbursts often occur just prior to tornado formation and
just prior to final dissipation. Tornadoes often take a fairly sharp
turn to the left of their previous path concurrent with a downburst and
just prior to dissipation.
Perform your damage survey only AFTER search and rescue activities have
concluded, but as quickly thereafter as possible. Clean-up efforts may
destroy the evidence you need for your survey. Keep a low profile and
stay out of the way of clean-up efforts. If you enter an area shortly
after an event, there will likely still be people busily
cleaning up the mess. You should express sympathy if approached and not
enthusiasm for the destruction. Do not enter private property without the permission of the owner.
To be of any use, you must record the exact location of damage. That's
where GPS comes in handy, since street signs and address markers may not
be available. You can also identify the location as X miles from Y road
intersection in Z direction. You should always try to identify where
the damage path began and ended. Use the Fujita damage scale to categorize damage intensity. Document your survey with photos or video
with wide shots of the area and detailed shots of unusual or significant
damage (straws in telephone poles, the nature of damage to trees
(uprooted or broken off trunks and large limbs), engine blocks torn from
vehicles, the presence of absence of anchor bolts in foundations,
sandblasting of objects with small debris, etc.). Write a brief but
detailed factual report devoid of speculation, attach photos and submit a signed, dated
copy to your local NWS within as short a time as possible after your
survey is completed.
Ask your NWS contact for advice on improving your survey and report.
http://www.pulse.net/storm/jarrell.htm
A visual damage report without much detail on location and intensity. This visual survey was done several days after the event, after much of the debris had been moved.
Updated: 29 Nov 2003 09:50 AM
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