Lightning Forensics FAQ
Lightning is essentially a giant spark of electricity,
created by the thunderstorm process. Thunderstorms form when significant
condensation, resulting in the production of a wide range of water droplets
and ice crystals, occurs in an atmosphere that is unstable and supports
deep, rapid upward motion. This often occurs in the presence of three
conditions: sufficient moisture accumulated in the lower atmosphere,
reflected by high dewpoint temperatures; a significant fall in air temperature
with increasing height, known as a steep lapse rate; and a force such
as mechanical convergence along a cold front that will focus the lift.
When these weather factors come together
and initiate a thunderstorm, the thunderstorm cloud develops charge
in the cloud. Typically, positive charge builds at the top of the cloud
and negative charge at the bottom of the cloud early in the thunderstorm
lifecycle. (Think of a standard Duracell battery – charges
at opposite ends). A stepped leader of charge leaves the cloud
and rapidly travels towards the earth’s surface following the
least path of resistance. This first stepped leader stroke approaches
ground in discrete steps of about 100 to 150 feet or more. This channel
is usually not visible to the human eye until it connects with the earth’s
surface (opposite charge) and the circuit completes and the electricity
flows (the lightning strikes). Charge can travel through this ionized
channel one or multiple times. Each independent pulse of electricity
is called a stroke. Multiple strokes through the same channel
are grouped as a flash.
Thunder is the audible result of the massive and
extremely rapid heating of the channel of air in which the lightning
has traveled. The result is an explosion of the air. Lightning
strikes and then thunder follows. Depending on your proximity to the
lightning ground strike point, these may occur simultaneously (if you
are very nearby) or up to many seconds later (further away) given that
the speed of light travels faster than the speed of sound.
The United States Precision Lightning Network
(USPLN) is a network of ground-based time of arrival sensors that detect
the electric wave form given off by a lightning event.
Lightning has a unique wave form that is
discriminated from all other electric wave forms (noise) to determine
that a lightning event has occurred. As the wave form travels
over the earth’s surface, each sensor uses a highly accurate GPS
(global positioning system) clock to time-stamp the event. The
individual sensor data is instantaneous sent to our central analyzers
for correlation with other sensors to determine where the stroke of
lightning occurred. While only three sensors are required to detect
the lightning strike and produce an accurate ground strike location,
the majority of lightning events are detected by 20+ sensors.
Typical USPLN installation.
Lightning detector on the left, GPS clock on the right.
Our state-of-the-art control center and network hub is
located in Melbourne, Florida. A fully redundant control center
operates in tandem in Oklahoma City, Oklahoma. Constant self-monitoring
performance technology exists within each sensor, all communication
methods are monitored in real-time and the network hub performance is
also continuously examined through automated procedures.
LightningTrax™ is an address and
date(s) specific verification of the occurrence of lightning on the
earth’s surface. LightningTrax™ reports make use of
the precision performance of the USPLN to accurately validate the presence
or absence of cloud-to-ground lightning strikes.
LightningTrax™ reports and LightningExpress™
Service are 95% accurate in reporting the presence (one or more strokes
detected within a 1 mile radius) or absence (zero strikes detected within
a 5 mile radius) of lightning.
A basic LightningTrax™ reports sells
for $95 and includes the written report for up to a 72 hour search period,
a print-out of lightning strike data and a full color map. Please
see our Pricing page for full details.
LightningTrax™ reports are purchased
on-line. Upon submitting your request, the USPLN database is accessed
and the report created “while you wait”. Most reports
are available with 1 minute of your request and the reports can be downloaded
and/or stored on-line in your password protected account.
USPLN offers either account privileges
with terms of Net30 for approved repeat customers and credit card payment
for occasional customers. Customers paying by credit card must
enter their credit card number on each purchase, as credit card information
is not stored on our servers. Pre-payment by check or money order
is also accepted.
Both products are available for any location/address
within the contiguous United States.
The USPLN archive data are available from
05-01-05 forward. If you need verification of a date prior to
this time, please contact us at 888.255.7099.
The precision accuracy of the USPLN allows
for affirmative confirmation of the presence of lightning by searching
a one mile search radius around a specific latitude/longitude coordinate
(address). Because lightning can strike nearby and induce a surge
over a large area, the USPLN first checks for direct strikes by searching
a one (1) mile radius and if no lightning is found, the radius is auto-enlarged
to a five mile search radius to detect any nearby lightning that could
have impacted the address of interest. This provides the most
accurate lightning reports possible.
Lightning and thunder can be seen and heard
from significant distances, depending on visual and audible attenuation
factors (humidity, cloud cover, ground clutter [trees, buildings, etc]).
The property owner may have observed distant lightning or a variety
of cloud lightning (lightning that does not come in contact with the
earth’s surface) overhead. We also suggest double checking
your facts as to the date of the search and the address of the property
in question.
We stand behind every report we produce.
If you need technical expertise to assist in a court case, please contact
us at 888.255.7099 or info@weatherforensics.com
for phone consultation, deposition and court appearances.
Yes, USPLN has two Certified Consulting
Meteorologists on staff plus other highly trained meteorologists and
lightning experts to assist you. Hourly fees quoted upon request.
USPLN lightning stroke detection occurs
through the scientific measurement and precise location plotting on
the earth’s surface. Most times, lightning reports from different
lightning networks will be highly similar; however, any given lightning
strike may be measured slightly differently. An “apples-to-apples”
comparison would be to compare the binary results (presence or absence
of lightning) of a given lightning report from each network.
While the USPLN is the newest and most state-of-art lightning detection
network, customers of lightning verification reports should not make
the assumption that the USPLN output is ground truth and the other network
is “inaccurate” – and vice versa.
For verification of 100+ claims per year,
we recommend our LightningExpress™ Service. LightningExpress™
allows direct access to the USPLN database of lightning strikes, all
for one set annual fee.
Hail Forensics
FAQ
HailTrax™ and HailExpress™ utilize a patented HailSwath
Predictive Algorithm (HPA) in combination with NEXRAD Doppler radar
and observed hail data from National Weather Service (NWS) observers.
HailTrax™ then extracts hail size and the geographic coordinates
where hail fell. Data disseminated by the National Climatic Data Center
(NCDC) and most commercial weather vendors, only contain observed hail
reports from NWS observers.
The NWS accepted standard definition of damaging
hail is considered to be ¾" and greater. Hail above 2" is a relatively
rare occurrence, but can cause significant damage when it occurs.
HailTrax™ reports are the most sophisticated
and accurate hail verification reports available. Scientific evidence
indicates hail detected and reported using NEXRAD and its' attendant
hail algorithm to be 92% or more accurate at estimating the size of
hail stones and greater than 96% accurate at detecting a hail storm
over a 24 hour period. See Technical Papers
for more details.
HailTrax™, Hail Analysis and all other forensic
reports are sent to you via e-mail within three business days if your
report date is after December 31, 2000. Please allow up to ten business
days for searches prior to January 1, 2001. If your report cannot be
completed in three business days, you will be contacted by a WDT representative.
Approved accounts are billed with terms of Net 30.
An invoice is provided via e-mail with your completed HailTrax™
report. Once you receive your invoice, payment is accepted by cash,
check credit card, cashiers check or money order. For products over
$500, after order submission you will be contacted by our accounting
department for credit card number and billing authorization.
We stand behind every report we produce. HailTrax™
and HailTrax™ litigation reports are designed purposely for address-specific
losses. HailExpress™ service is designed to give general information
regarding hail location and therefore should not be used for address-specific
events. If you need technical expertise to assist in a court case, please
contact us at info@weatherforensics.com
for phone consultation, deposition and court appearances. Hourly fees
quoted upon request.
100% customer satisfaction is guaranteed. Please
notify us within 10 days if you have any issues that are not meeting
your expectations.
Any location/address within the contiguous United
States. Call for availability of data in Alaska, Hawaii and Puerto Rico.
HailTrax™ reports are intended for events
spanning a day to several days. For losses spanning several weeks or
months, our meteorologists can create a customized Hail Analysis Report.
Hail Analysis Reports do not utilize the HailTrax™ algorithm,
but are comprised of our meteorologist's review of the available National
Weather Service hail data records, compiling a report and presenting
a meteorological opinion.
Daily HailExpress™ Service is created by 5
pm Central Time for the previous 24 hour period. WDT obtains all published
NWS human observations at the time the report is created. However, according
to NWS policy, hail observations may be added to the hail report record
for up to 90 days beyond the actual hail event date.
HailExpress™ Service can start as soon as
the License Agreement is signed and the meteorologist establishes and
account for you - usually 7-10 days. If you need immediate access, please
contact us for expedited service.
For sales related questions call: 1-888-255-7099
For technical support questions call: (405) 579-7675 ext 227
Email us at info@weatherforensics.com.
While weather reports may all seem similar, the
technology needed to produce a HailTrax™ Report is significantly
different from the technology of producing a LightningTrax™ report.
HailTrax™ Reports require review and input by a trained meteorologist,
to evaluate the output of add quality assurance to the data. HailTrax™
Reports are delivered, via email, within 2-3 business days.
Tornado Forensic FAQ
WDT’s Tornado reports are generated
by expert meteorologists using damage surveys/assessments and NEXRAD
Doppler Weather Radar data. These reports fully utilize the power
of GIS (Geographic Information Systems) to produce precise and reliable
damage paths that are provided either as color coded maps or as GIS
formatted polygons (shapefiles).tornado reports
WDT also offers TornadoExpress™ Service for any
tornado that causes damage in a large population area (100,000+).
These reports are sent via email or provided via an Internet browser.
Once provided, the information can be accessed anywhere and at any time.
When tornadoes occur, a regional color map is created within 10 days
along with city-level maps for cities within the region. All maps
are provided in PDF format, allowing the customer to zoom in and closely
examine where an expert meteorologist has determined where the damage
has occurred. All TornadoExpress™ maps display a color coded
tornado path to assist in better defining areas where damage occurred.
In addition to the color-coded maps, GIS digital data can be provided
to the customer for overlay on their assets or other areas of interest.
To assist in the determination of the tornado path
and related impacted areas, WDT’s tornado reports are used by
insurance carriers, claims adjusters, and others in need of tornadic
location data.
Hurricane Forensics FAQ
The National Hurricane Center (www.nhc.noaa.gov),
a division of the National Weather Service, is the leading US government
authority on hurricanes. Their website provides useful information on
current and historical hurricanes.
In addition to thewww.nhc.coaa.gov, there are several
other sites providing good general information on hurricanes. One of
the best NWS sources for hurricane FAQs is http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqHED.html
