Weather Part I: Mitigating the Unthinkable
John Gerrish, certified meteorologist
scientific innovations occur all the time and new products are brought
to market making our lives better and easier — computers, the Internet,
cell phones, compact discs, lasers. Where would we be without satellite
communications, plastics, synthetic and composite “man-made” materials
that are stronger and lighter than steel?
new products don’t come without a cost. Many of these materials
are developed using petroleum-based materials, caustic chemicals,
corrosive acids, and complex chemical compounds which are hazardous
to people and the environment. The waste products from these processes
and materials are also harmful; containing and disposing of them
is problematic. Accidents happen. Even worse, what about deliberate
acts of sabotage and terrorism?
Materials (HazMat) primarily come in three forms: radiological/nuclear,
biological, and chemical.
1995 to 2004, there have been over 150,000 HazMat related incidents
and accidents on our nation’s highways, waterways, airways, and
railways. Over 5,000 have been classified as “Serious Incidents.”
sites store or transport HazMat chemicals in pressurized liquid
or solid form. When these chemicals are exposed to air, they
can instantly vaporize and be carried on the wind.
store hazardous materials. Pool and Spa outlets store
enormous amounts of chlorine-based products. Many fertilizers
are chemically based and can be extremely volatile when mixed
with petroleum products, as evidenced in the Oklahoma City
bombing. The methamphetamine epidemic in our country requires
caustic chemicals that are extremely dangerous and toxic.
many chemicals or chemical compounds are highly flammable or even
explosive, city ordinances now require businesses that store toxic
chemicals to mark their buildings with symbols to notify emergency
and fire personnel what types of chemicals are stored inside.
11, 2001 changed our world forever. We were served notice of an
emerging and deadly threat. Not only do we have to prepare against
accidents and incidents, now our emergency responders must become
prepared and trained against deliberate acts of terror and weapons
of mass destruction.
state, and federal officials have formed agencies to prepare for
the unthinkable — from railroad accidents with hazardous materials,
to highway incidents, to deliberate acts of terror.
— bacteria and virus strains such as Anthrax, Typhoid, Small Pox,
Bubonic Plague, and Cholera — can also be carried on the wind or
through our water systems. Plagues wiped out over 25 million people,
one-third of Europe’s population, between 1347 and 1352. In Asia,
millions died of Cholera. Although an accident of this magnitude
is unlikely, a deliberate act of terrorism is a frightening thought.
the early 20th century, unethical warfare brought these biological
agents to the battlefield to kill the enemy en masse. Today, these
airborne virus and bacterial agents can contaminate an entire geographical
region and spread rapidly, infecting a large population center in
a very short time.
nuclear accident is unthinkable, but the threat is extremely
real. Chernobyl is a prime example where nuclear radiation spread
downwind for hundreds of miles, contaminating everything in its
path. A “dirty bomb” is a relatively small nuclear device designed
to create a low-yield explosion and a high-contamination debris/dust
cloud. Minute dust particles contaminated with radiation would be
carried far downwind to pollute everything they touch. Ground Zero
and the surrounding area could be uninhabitable for years.
first line of defense is our local fire and police departments.
State, and Federal Emergency Management agencies, fire departments,
and HazMat teams are trained to recognize a threat and take
action. They respond to contain and neutralize the effects
of potentially deadly toxins. Accident and Incident Commanders
are highly trained in mitigation techniques. Through all of
this, one constant holds true: airborne contaminants pose
the greatest threat to the population.
precise weather conditions is vital to HazMat mitigation.
humidity, and other atmospheric conditions are paramount in determining
downwind contamination areas, chemical dispersion rates, and evacuation
areas. Knowing the character of the atmosphere is like knowing battlefield
Toxic Chemical dispersion programs have been developed to decipher
the character of airborne chemicals and to predict their character.
These modeling programs complement the decision-making tools an
Incident Commander has at his disposal. However, with ever-changing
weather conditions, the variables soon get beyond the scope of the
software. By automatically ingesting weather data into computer
programs such as CAMEO/ALOHA (Computer-Aided Management of Emergency
Operations/Areal Locations of Hazardous Atmospheres) and MARPLOT
(Mapping Application for Response, Planning, and Local Operational
Tasks), Incident Commanders have the ability to make computer-aided
decisions that affect both the mitigation process and any evacuations
that may be necessary.
monitoring equipment is a real force-multiplier.
What used to take multiple personnel to compute and plot a
toxic plume is now done automatically by computer generation.
Mission-critical data is now instantly and continuously available.
Data can be instantly transferred to keep all Command levels
apprised of vital weather conditions and critical toxic chemical
weather stations mounted on emergency vehicles, Mobile Command
Posts, and stand-alone portable weather systems are used to
track weather conditions in tactical situations or in the
middle of a “hot zone” from a safe distance.
and Wind Speed. By knowing the wind’s character, experts can
plot a toxic plume model to determine the scope of the contamination
readings are crucial because different chemicals vaporize at different
temperatures. Some vaporize instantly when they come in contact
with air, others vaporize at different ambient temperatures. Also,
the warmer the atmosphere, the more vapor the air can hold, thus
the more intense a plume cloud can become.
Humidity readings are crucial because they indicate the percentage
of moisture contained in the atmosphere, which can easily become
contaminated by the toxic cloud vapor.
Temperature indicates the temperature at which the atmosphere
becomes totally saturated (100% humidity) and dew or fog may form.
In a toxic environment, this means the toxic chemicals will be trapped
close to the ground in a saturated atmosphere and persist until
the weather conditions change.
Pressure is a strong indicator of the upward and downward air
movement in the atmosphere through air density. When pressure rises,
the air aloft is sinking downward. This creates higher pressure
and often traps the air close to the surface. Consequently, if the
pressure is falling, this means the air is rising upwards, thus
creating the ability for the chemicals to rise up and disperse into
washes chemicals out of the atmosphere; however, this means that
it contaminates the ground and/or ground water.
Water (or rainfall)
also activates some chemicals - for example phosphine. This gas
is used for pest control and as a fumigating agent. For farm use,
it is often sold in the form of aluminum phosphide pellets, which
yield phosphine gas on contact with atmospheric water.
conditions won’t stop accidents and incidents from happening, but
it provides a powerful and valuable tool in mitigating their effects
and protecting lives.
Part II in the next issue of Recap and view John’s Powerpoint presentation