BOOK: Operations I
SECTION: Natural Disasters (CHIEF NOTES)
Page 1 of 2
Natural Disasters
(Updated through 8/7/04)
WEATHER
 Disaster as defined by American Red Cross is "an occurrence such as a hurricane, tornado, storm, flood, high water,
wind-driven water, tidal wave, drought, blizzard, pestilence, famine, fire explosion, building collapse, transportation
wreck, or other situation that causes human suffering or create human needs that the victims cannot alleviate without
assistance".
 Some catastrophes can be anticipated, some cannot.
 The National Weather Service (NWS), a component of the National Oceanic and Atmospheric Association (NOAA),
studies natural disasters.
 Weather is always dynamic (changing).
 Weather is defined as "the state of the atmosphere surrounding the earth, and is controlled by the variable nature of the
atmosphere".
 Atmospheric pressure, wind speed/direction, humidity, visibility, clouds, and precipitation all effect weather
conditions.
WINTER STORMS
 Most major disasters in the US result from severe winter storms.
 Winter storms are generated from disturbances along the boundary between cold polar and war tropical air masses.
 Winter storms move in a counterclockwise sweep.
 Since 1936, snowstorms have caused 100 deaths per year and 200 deaths per year is not uncommon.
 More than 1/3 of deaths from winter storms are from automobile and other accidents.
 Approximately 11% of reported winter deaths are caused by exposure and fatal freezing.
 Carbon monoxide poisoning in stalled cars is a cause of winter deaths.
 A "Watch" alerts the public that a storm has formed and is approaching an area.
 A "Warning" means that a storm is imminent and immediate action should be taken to protect life and property.
FREEZING RAIN
 Freezing rain/drizzle occurs when surface temperatures are below freezing and freezes on contact with the ground.
 Freezing rain ranges from a thin glaze to 1 inch thick.
 Over 85% of ice storm deaths are traffic related.
 Sleet is identified as frozen rain that bounces when hitting the ground.
 Sleet does not stick to trees and wires.
 The terms ice, freezing rain/drizzle indicates a coating of ice is to be expected on the ground and other surfaces, and
the addition of the term "heavy" to these terms indicates the weight of the coatings will cause significant damage to
trees and overhead wires.
 At temperatures just below freezing, a layer of snow and ice on roads will be churned and polished by car tires into a
slick layer.
 Snow, without qualifying words such as occasional or intermittent, means snow will not let up for several hours.
 Heavy snow warnings indicate a fall of snow of 4 inches or more in a 12 hour period.
 A heavy snow is generally associated with 6 inches or more.
 Snow fall of 2 to 3 inches may be termed heavy snow in areas with infrequent snow or metropolitan areas with heavy
traffic.
 Snow flurries may reduce visibility to 1/8 mile or less.
 Blowing snow is defined as "snow lifted from the surface by the wind and blown to a degree that horizontal visibility
is greatly restricted".
 Blowing/drifting snow, after a substantial snow fall, may be termed a ground blizzard.
 Blizzard warnings are issued with winds of at least 35 mph in conditions of heavy snow fall or blowing/drifting snow.
 Severe blizzard warnings are issued with winds of at least 45 mph and at temperatures of 10oF or lower.
CHILL INDEX
 With an outside temperature of 0oF with a 20 mph wind, wind chill is -35oF.
 Winds of 40 mph or greater have little additional effect on wind chill factors.
 Properly clothed individuals have little danger of freezing unless the wind chill drops below -20oF.
 Exposed flesh can freeze in 1 minute with wind chills less than -20oF.
 Exposed flesh can freeze in 30 seconds with wind chills less than -70oF.
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BOOK: Operations I
SECTION: Natural Disasters (CHIEF NOTES)
Page 2 of 2
FURNACE CHECKLIST
 The inlet side of a furnace filter is coated with a sticky substance to trap dust particles.
 The motor nameplate or instruction booklet for a furnace should be checked to see if the unit needs oiling.
 Check the set crew on fan and motor pulleys.
 Check fan belts for cracking or stiffness.
 Clean fresh air registers.
 Pilot lights should be lit before cold weather arrives.
 Units with automatic spark ignitors do not require a pilot light.
 Never run an air conditioner if the outside temperature is 55oF or below.
ITEMS TO CHECK AROUND THE FIRE STATION
 Check window/door seals, weather stripping, flues on gas hot water tanks, caulking on outside openings, outside water
sillcock, gutters and downspouts, furnace rooms for cleanliness, and tire chains for each rig.
 Ensure personnel have extra gloves, liners in bunkers, insulated underwear/sweatshirts, and nomex hood and helmets.
 The water level in the storage battery and oil level in generators must be checked.
TORNADOES
 Tornadoes are most likely to occur mid-afternoon between 3pm and 7pm.
 Direction of movement of tornadoes is usually from Southwest to Northeast.
 The width of a tornado path in Oklahoma averages 135 yards.
 The destruction path in Oklahoma averages 4.7 miles, however they have reached 140 miles.
 The speed of forward motion of tornadoes in Oklahoma averages 30 mph, however, can range from almost no motion
up to 70 mph.
 Clouds associated with tornadoes are dark, heavy, cumulonimbus clouds.
 Precipitation with tornadoes usually occurs as a rain just preceding the storm and a heavy downpour immediately to
the left of the tornado's path.
TORNADO SAFETY RULES
 A 3 to 5 minute steady blast on warning sirens mean TORNADO!
 Keep windows open, but stay away from them.
 Secure loose outside items as time permits.
 Auditoriums, gymnasiums, and other structures with wide, free span roofs should be evacuated.
DISASTER CONTROL
 If a tornado hits, the officer should report damage sustained and impairment of response capability.
 Obstructed station doors should be cleared immediately with chain saws, bulldozers, cranes, or other debris-removal
equipment.
 Aerial reconnaissance may assist in determining a clear path of travel for responding vehicles.
 Helicopters may be used to lay lines and fly in crews in inaccessible locations.
 A post-disaster inventory of equipment lost or damaged should be made.
 Do not take lanterns, torches, or lighted cigarettes into buildings damaged by a natural disaster.
OKLAHOMA NOAA WEATHER RADIO PROGRAM
 Broadcasts on NOAA radios are made on 1 of 3 frequencies: 162.40, 162.475, or 162.55 MHz.
 Many weather radios have a "standby" or "alert" feature that turns the radio on when given a signal (1,050 Hz) tone.
 NOAA radio forecast can be heard up to 40 miles from the transmitting site.
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