Coshocton County Emergency Operations Plan
TORNADOES and SEVERE STORMS
ANNEX L
APPENDIX B - TORNADOES and SEVERE STORMS
I. PURPOSE
The purpose of this appendix is to identify response and procedures used in case of a tornado watch, warning, or high wind incident.
II. SITUATION and ASSUMPTIONS
SITUATION
1. Many severe thunderstorms with high wind down drafts have been recorded doing damage and harm to people and property and even causing death. Many destructive severe storms did the damage attributed to tornadoes. Past history in CoshoctonCounty does not record tornadoes.
2. Severe thunderstorms are usually accompanied by lightning. Lightning has killed persons in CoshoctonCounty. Lightning kills people when they fail to take cover.
3. Since tornadoes can occur at any time of the year or time of day, Coshocton County is at risk at any given time.
4. Tornado conditions are common in the spring. Therefore, the majority of the public education on tornado awareness is done in the spring of the year.
5. Preparedness measures are highly encouraged and information is available on how to develop a family plan and what supplies should be contained in a family disaster supplies kit.
6. The EMA web site ( offers preparedness information suited to seasons of the year and suggestions for emergency kits for several different conditions.
7. County Sky Warnvolunteers are the “eyes for the county” when severe weather threatens. The local REACT is also active, as are the Sheriff’s deputies on patrol, some firemen, and certain individual citizens who have received Sky Warn training. A list of current Sky Warn volunteers is available in the EMA office.
ASSUMPTIONS
1. The National Weather Service will not always forecast CoshoctonCounty to be in a severe weather situation because of their distance from this county and the limitations of monitoring and forecasting equipment.
2. In the event of that local weather getssevere or when a trained spotter has notified the Sheriff’s Department that severe weather is threatening, the Sheriff's Office will initiate a warning. All notification messages are issued by the Coshocton County Sheriff's Office, which is staffed 24 x 7. This will enable residents time to seek shelter.
3. There is a need to build public consciousness about tornadoesand the effects of severe storms. CoshoctonCounty participates in the Annual Statewide Severe Weather Awareness Week each spring. Both public and private schools hold drills that coincide with the Statewide Tornado Drill. Each school has its own disaster plan and these plans are tested at this drill time.
4. Nursing homes and extended care facilities also participate in this safety week.
5. Public education awareness is made available through news releases to local media (press, radio and television), public service announcements and special speaking engagements.
6. Many people are killed each year by not heeding warnings. These people failed to take shelter and became vulnerable and occasionally become casualties.
7. It is equally important to avoid using electrical appliances. Power surges from lightning can damage electrical appliances or overload the A/C compressor, resulting in a costly repair.
III. CONCEPT OF OPERATIONS
1. National Weather Service releases continuous notices when weather conditions become severe. Using radio and television, the public can monitor local conditions.
2. All hazard radios are valuable for receiving weather alerts. All hazard radios have been installed by the EMA office in more than twenty county buildings, all schools, and vital public service departments such as the sheriff, fire and EMS.
3. Trained Sky Warn spotters and Sheriff's deputies begin to monitor and pay special attention to weather conditions.
4. Once there is evidence that a warning is necessary, the sheriff will release a notice using the Emergency Alert System, Code Red, radio and cable television. Radio is the best media for public source of weather warnings and notification for the public.
IV.ORGANIZATION and ASSIGNMENT OF RESPONSIBILITIES
Refer to Basic Plan, Basic Plan 2.8 Assignment of Responsibilities
Annex A - Direction and Control.
V. ADMINISTRATION and LOGISTICS
Refer to Basic Plan, Annex A - Direction and Control.
VI. PLAN DEVELOPMENT and MAINTENANCE
Refer to Basic Plan, Section 2.3.
VII. AUTHORITIES and REFERENCES
Refer to Basic Plan, Section 2.5.
VIII. ADDENDUMS
Tab 1 - Severe Storm/Tornado Information
Tab 2 - Severe Thunderstorm Checklist
Tab 3 - Tornado Emergency Checklist
Tab 4 - Lightning Checklist
Tab 5 - Sky Warn Storm Spotters
Tab 6 - Hazardous Weather Web Links
Tab 1
TORNADO / SEVERE STORMINFORMATION
Thunderstorms usually form when the air is moist and warm. The warm air rises, then cools, letting the moisture it contains form clouds. Thunderstorms are built up by huge, gray-black cumulonimbus clouds that can stretch up so high into the atmosphere that water in the highest regions becomes ice crystals. These crystals usually melt to form rain, but when they remain frozen, will fall as hailstones.
A supercell storm is one that has managed to gain control of a large area and keeps to itself, not sharing its fuel (warm, moist surface air) with surrounding storms. The supercell efficiently takes in surface air (its fuel), sucks it high up into the storms structure, “processes” it, and then re-deposits the air and moisture through its downdraft mechanism. Supercells are recognizable by an enormous central column of a cauliflower-shaped cloud. It sucks up air through an uptake or inflow area in its rear (an area usually marked as the “rain free base”, where little or no precipitation is falling). The heated and energized air from the surface streams to the top of the cloud structure, possibly 50,000 feet into the atmosphere and becomes denser than the air around it and then slows down. Condensed moisture forms droplets of rain or ice crystals. Supercells can send down an inch of rain in a mere ten minutes or shower the ground withbaseball-sized hailstones. The greater the updraft, the larger the hail will be. Throughout the storm’s mature and dying phases, severe weather - including tornadoes - is possible.
A lot can be learned about the severity of the storm by simply looking at cloud structures. Wall clouds are most likely to produce tornadoes. Wall clouds lurk in the area where updraft and downdraft come together (between the ‘rainy’ areas of the storms and the rain free base). The wall cloud could maintain its position in the downdraft/updraft area for quite some time. The entire wall cloud will likely be moving in a huge circular motion.
A tornado is a violently rotating column of air extending from a thunderstorm to the ground and is capable of destroying homes and vehicles and can cause fatalities. Tornadoes can occur at any time of the year. They may appear nearly transparent until dust and debris are picked up or a cloud forms in the funnel. Tornado behavior is never precisely predictable. The typical tornado moves SW to NE, but can move in any direction. It may or may not touch the ground, touch and vanish, rise and touch again, or even spin in one spot for several minutes. Tornadoes most likely occur between 2 and 10p.m., but can occur at any time of the day or night. They typically have a loud, continuous roar or rumble that doesn’t fade in a few seconds like thunder. Frequently, small, bright, blue-green to white flashes at ground level are seen due to power lines being snapped. The tornado’s shape can also differ, looking like a long, thin rope or an upside-down bell. The length from the base of the funnel to the tip of its “trunk” can be from 800 to 2,000 feet. Faster upper winds usually blow the top of the funnel more quickly than the lower portion, making the tail seem to drag behind.
TORNADO / SEVERE STORM INFORMATION
A well-known scale is used to represent the destructiveness of tornadoes. This scale is called the Fujita-Pearson Tornado Scale or the F-scale. The Fujita scale should be used with caution, however. Specific wind speeds are still largely undetermined. Different winds may be needed to cause the same damage depending on how well built a structure is, wind direction, wind duration, battering by flying debris, and other factors. The process of rating the damage is largely a judgment call. Even meteorologists and engineers highly experienced in damage survey techniques may come up with different F-scale ratings for the same damage.
The following table shows the F-scale in more detail:
F-scale / Type of Tornado / Intensity / EstimatedWind
Speeds / Description of Damage
FO / Gale Tornado / Weak / 40-72 mph / Some damage to chimneys; breaks
tree branches; damage to signboards.
Fl / Moderate
Tornado / Weak / 73-112
mph / Peels shingles off roof; tips over
mobile homes and cars; downs trees
and power lines.
F2 / Significant
Tornado / Strong / 113-157
mph / Roofs torn off; mobile homes
destroyed; trees uprooted; cars
blown off roadways.
F3 / Severe Tornado / Strong / 158-206
mph / Walls torn down from homes; rural
buildings demolished; trains
overturned; cars thrown.
F4 / Devastating
Tornado / Violent / 207-260
mph / Well-constructed homes leveled;
large flying debris; cars twisted.
F5 / Incredible
Tornado / Violent / 261-318
mph / Homes lifted off foundation and carried
considerable distances;cars thrown
100 yards.
F6 / Inconceivable
Tornado / Violent / 31 8-379
mph / None ever recorded; the wind
speeds are very unlikely. It would be
difficult to measure; no objects would
be left to study.
Tab 2
SEVERE THUNDERSTORM CHECKLIST
FACTS — Thunderstorms are intense local storms, averaging 20 miles across and reaching as high as ten (10) miles. They occur anywhere.
A thunderstorm is a storm with lightning caused by changes in the air pressure. Severe thunderstorms can bring heavy rains (that can cause flash flooding), strong winds, hail and tornadoes. At any given moment, nearly 1800 thunderstorms are in progress over the face of the earth.
WHAT SHOULD CITIZENS DO?
• Turn on the local(WTNS)radio station for the latest advisories or weather bulletins.
• Keep an eye of the sky and look for darkening skies, flashes of light, or increasing wind.
Listen for thunder.
• If you hear thunder, you are close enough to the storm to be struck by lightning. Go to a safe
shelter immediately.
• Keep car windows closed if you are in a car.
• Avoid taking a bath or shower or running water for any other purpose.
• Turn off air conditioners. Power surges from lightning can overload the compressor.
• Draw blinds shades or curtains over windows. If windows break due to objects blownby the
wind, the closed blinds or curtains will prevent glass from shattering into your home.
• If you are outside, take shelter.
• If you are boating or swimming, go to land and find shelter immediately.
• Go to a low-lying, open place away from trees, poles, or metal objects.
• Make sure the place is not flood prone.
• Be a small target and squat low to the ground. Place your hands on your knees with
your head between them. Make yourself as small a target as possible.
THUNDERSTORM INTENSITY LEVEL CHART
LEVEL ESTIMATED PRECIPITATION INTENSITY - RATE PER HOUR
1 Light less than 0.1”
2 Moderate 0.1 to 0.5”
3 Heavy 0.5 to l.0”
4 Very Strong 1.0 to 2.0”
5 Intense 2.0 to 5.0”
6 Extreme more than 5.0”
WIND SPEED ESTIMATIONS CHART:
MPH EVALUATION
0 Smoke rises vertically
1 - 3 Direction shown by smoke drift
4 - 7 Wind felt on face, leaves rustle
8 - 12 Leaves and small twigs in motion, light flags extended
13 - 18 Dust raised, loose paper raised, small branches move
19 - 24 Small leafy-trees move, crested wavelets form on lakes and ponds
25 - 31 Large branches in motion, whistling in telephone wire and wire fences
32 - 38 Whole trees in motion, inconvenience in walking into the wind
59 - 46 Twigs break off; impedes walking
47 - 54 Slight structural damage (chimneys, shingles, etc)
55 - 63 Trees uprooted, widespread structural damage, mainly roofs
64 - 72 Damage to structures major and widespread, roofs and windows damaged
73 - above Major and extreme damage
ESTIMATING HAIL SIZE:
Pea size ¼ inch
Marble size½ inch
Dime size ¾ inch
Quarter size 1 inch
Golf ball size 1 ¼inches
Baseball size 2 ¾ inches
Tab 3
TORNADO EMERGENCY CHECKLIST
TORNADO WATCH:
Means to use caution, a tornado or severe weather is possible.
- Listen to cable TV or regular local television channels for weather updates.
- Listen to WTNS radio, FM 99.3 and AM 1560.
- Watch for bad weather, if it looks bad, start thinking about what to do if a storm enhances.
- Secure loose objects outside (such as trash cans, lawn furniture, etc.)
- Close blinds and curtains.
- Close room-dividing doors.
- Close all exterior and interior doors.
- Designated safe area should be checked to assure that they are ready if needed.
- Important records should be secured.
- 35% of all tornadoes occur without formal warning.
TORNADO WARNING:
Means a funnel cloud has been spotted and to seek shelter immediately.
- All persons should now be moved into designated areas.
- Staff should go to designated areas.
AFTER A TORNADO OR DANGER IS PAST:
The all clear signal given, if damage has occurred to a home or building, the following checklist should be followed:
1. Never use matches, candles, or cigarettes in the area where tornado damage has occurred since there could be a gas leak.
2. Shut off the main gas line to the damaged building(s).
3. Shut off the main electrical panel if any part of the electrical system is damaged.
4. Assist in evacuation of all persons from damaged buildings.
5. If you need to evacuate your building see ‘Evacuation Checklist’.
6. Shut off the main water line only if water lines are broken.
7. Watch for fallen power lines.
8. Assign people to keep people away from dangerous areas until emergency crews arrive.
Tab 4
LIGHTNING CHECKLIST
FACTS — Lightning has been known to strike up to 15 miles away from a parent cloud. Nothing else can compare to the instantaneous release of intense energy as lightning. It travels at more than 100,000 miles per second, 3 to 4 miles in length and produces more than 100 million volts at a temperature five times greater than the surface of the sun.
Lightning strikes about 8 million times each day or about 100 times per second around the circumference of the globe — a rate of discharge that represents about 4 billion kilowatts of continuous power.
Lightning is the atmosphere’s way of balancing the electrical charge between itself and the earth’s surface through thunderstorms. It seeks the shortest path to the earth’s surface and is attracted to any object taller than ground level.
The average length of a lightning bolt is 3 to 4 miles. The average diameter of a lightning bolt is 1 to 5 inches. Lightning travels at about 100,000 miles per second.
Despite the false evidence provided by the human eye, lightning leaps NOT from the sky to the earth but from the ground to the cloud.
Lightning is attributed for many structural and forest fires each year.
KNOWING WHAT TO DO IS IMPORTANT WHEN LIGHTENING IS OCCURRING.
Preparedness, before and after electrical storms, can help prevent disasters.
Persons should keep alert to the weather and, when threatening conditions first develop, radio weather updates are the best way to keep up on a storm status.
Keep an eye on the sky. Look for darkening skies, flashes of light, or increasing wind. Listen for the sound of thunder.
If you hear thunder, you are close enough to the storm to be struck by lightning. Go to a safe shelter immediately.
IF SOMEONE IS STRUCK BY LIGHTNING:
People do notcarry an electrical charge and can easily be handled safely.
Call for help by calling 911.
The person struck by lightning has received an electrical shock and may be burned both where they were struck and where the electricity left their body. Check for burns in both places.
Give first aid. If breathing has stopped, begin rescue breathing. If the heart has stopped beating, a trained person should give CPR.
Tab 5
SKYWARN STORM SPOTTERS
SKYWARN is a voluntary program, developed by the National Weather Service, to improve the warning program. SKYWARN volunteers serve as storm spotters for the NWS and local emergency management programs. Volunteers serve as important information gatherers by identifying specific weather conditions as they happen. Current information that is reported to Pittsburg NWS office is used to sharpen the accuracy of the next weather forecast.
Training is held semi-annually with the instruction done by the NWS personnel. The Coshocton County Emergency Management Agency (EMA) office schedules a training opportunity every two (2) years for interested residents.