Technology Spotlight:
New Lightning Safety Best Practice
Allows Dramatic Reduction in Lightning
Delays at Venues by Mike Eilts
Every year, stadiums,
concerts, speedways, and amuse-
ment parks are frequently threatened
by cloud-to-ground lightning. These
types of venues are incredibly vulner-
able to lightning due to the large num-
ber of people in attendance that are not
in any shelter. Across the United States,
over 400 people become victims of
lightning strikes each year. Of those
strikes, 15% are fatal and hundreds
more result in permanent injury. With-
out an adequate lightning safety plan,
venues can put thousands of people at
risk of becoming one of these victims.
WeatherOps offers a service that pro-
vides all of the real-time lightning
alerts and data that is needed to help
maximize safety and ensure that ven-
ues have the information they need to
delay and resume events
when conditions warrant.
The standard rule for light-
ning safety is if lightning is
within 8 miles of a venue,
then the site should be
evacuated and all activities
stopped. Activities should
only begin after no light-
ning has occurred within
8 miles for a period of 30
minutes. A recent change
in the standard for light-
ning safety guidance from
the U.S. National Weather
Service’s (NWS) Lightning
Safety Toolkit for large ven-
ues gives outdoor events an opportuni-
ty to continue their activities in advance
of the standard 30-minute delay IF the
threat has diminished and they are con-
sulting with a professional meteorolo-
gist that has access to real-time lightning
data.
On April 1st, WeatherOps launched a
new “Early All-Clear” service for our
outdoor event customers that provides
venues the opportunity, if conditions
are right, to resume activities up to 20-
25 minutes earlier than they could have
based upon the previous guidelines.
Following the new guidelines, Weath-
erOps meteorologists utilize real-time
lightning, satellite, and high-resolution
radar data along with their knowledge
of storm structures to assess lightning
threats. As ongoing risks decline, our me-
teorologists analyze the current environ-
ment for the potential redevelopment
of the lightning threat. Lightning threats
are considered to have diminished IF a
professional meteorologist determines
that the following conditions (and a few
others) are met:
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1. All lightning is more than 8 miles
away from the venue.
2. The storm motion is moving away
and ongoing lightning activity is not
near the venue.
3. The threat of new thunderstorm de-
velopment causing lightning at or near
the venue has ended.
When observations, forecast data, and
forecaster analysis indicate that the ex-
isting lightning threat and threat for
new lightning strikes has diminished,
and all of the guidelines above are
achieved, an “early all-clear” may be
issued to the customer at the meteorol-
ogists’ discretion. This message is deliv-
ered directly to the customer during a
call with a WeatherOps meteorologist.
In some instances, these alerts can save
valuable time when working to resume
an event. If an early all-clear is issued, it
is up to the venue to decide to contin-
ue the planned activity.
Resources:
National Weather Service Lighting
Safety Toolkit: http://www.lightning-
safety.noaa.gov/toolkits/Lightning_
Safety_Toolkit_Outdoor_Venues3-18.
pdf