Storms - Loudoun County Public Schools...Storms Mid-latitude cyclones (wave cyclones, cyclonic storms)-large type ... hurricane in N hemp, because wind blows counterclockwise around

Storms

Normal Mid-latitude

Storms

Mid-latitude cyclones (wave cyclones, cyclonic storms)- large type of low pressure storm system formed in of low pressure storm system formed in the mid-latitudes (tornadoes, hail, thunderstorms)

Thunderstorms

LIFE CYCLE:

Cumulus stage Mature stage Dissipating stage

Lightning

A discharge of electricity from a thundercloud to the ground, from cloud ground, from cloud to cloud, or within the cloud

Lightning - Inside

1. Avoid contact with corded phones

2. Avoid contact with electrical equipment or cords. If you plan to unplug any electronic equipment, do so well before equipment, do so well before the storm arrives.

3. Avoid contact with plumbing. Do not wash your hands, do not take a shower, do not wash dishes, and do not do laundry.

4. Stay away from windows and doors, and stay off porches.

5. Do not lie on concrete floors and do not lean against concrete walls.

Lightning - Outside

Stay away from metal objects, such as fences, poles and backpacks. Metal is an excellent conductor. The current from a lightning flash will easily travel for long distances

Do NOT seek shelter under tall isolated trees! The tree may help isolated trees! The tree may help you stay dry but will significantly increase your risk of being struck by lightning. Rain will not kill you, but the lightning can!

Do NOT seek shelter under partially enclosed buildings

Stay away from tall, isolated objects. Lightning typically strikes the tallest object. That may be you in an open field or clearing. Lightning Desperation Position

Tornado

Tornado

Fujita ScaleFujita Scale Wind Wind

(mph)(mph)

DamageDamage

F0F0 -- Light DamageLight Damage < 73< 73 Slight to chimneys, signs. Branches blown off trees.Slight to chimneys, signs. Branches blown off trees.

Fujita Tornado Intensity ScaleFujita Tornado Intensity Scale

F0F0 -- Light DamageLight Damage < 73< 73 Slight to chimneys, signs. Branches blown off trees.Slight to chimneys, signs. Branches blown off trees.

F1F1 -- Moderate Moderate

DamageDamage73 73 -- 112112 Tiles off roofs; mobile homes/caravans lifted; cars blown off roads.Tiles off roofs; mobile homes/caravans lifted; cars blown off roads.

F2F2 -- Considerable Considerable

DamageDamage

113 113 --

157157Mobile homes/caravans destroyed; cars lifted; large trees uprooted.Mobile homes/caravans destroyed; cars lifted; large trees uprooted.

F3 F3 -- Severe DamageSevere Damage158 158 --

206206Trains overturned; roofs blown off wellTrains overturned; roofs blown off well--built houses; heavy vehicles thrown.built houses; heavy vehicles thrown.

F4F4 -- Devastating Devastating

DamageDamage

207 207 --

260260

WellWell--built houses destroyed; large structures with weak foundations blown some distance built houses destroyed; large structures with weak foundations blown some distance

away.away.

F5F5 -- Incredible Incredible

DamageDamage> 261> 261

Strong framed houses lifted off foundations or blown away; Car sized missiles thrown over Strong framed houses lifted off foundations or blown away; Car sized missiles thrown over

100 meters.100 meters.

Tornado Prediction

Conventional radar can show ‘hooks’ of precipitation within strong thunderstorms, but sometimes only thunderstorms, but sometimes only shows hook once tornado hits ground –TOO LATE!

Doppler radar can show rotation within the clouds giving up to 20 minutes warning before tornado forms

Tornado

Tornado Watch indicates that conditions are right for a tornado to develop and that the sky should be watched. Be alert to changing weather conditions!

Tornado Warning indicates a tornado has been Tornado Warning indicates a tornado has been sighted or that radar indicates one has developed or could develop within minutes. Warnings will give the location of the tornado and the area immediately affected by the warning. When a warning is issued, move quickly to shelter!

What do I do?

Inside:

Move to an interior

room, preferably

underground or on

Outside:

Move inside if

possible

underground or on

the bottom floor

Protect your head &

neck from flying

debris

If in a car, get OUT

of the car & lie down

flat on the ground,

preferably in a ditch

away from the car &

anything that might

fall on you.

Hurricane

Large rotating storm of tropical origin with sustained

winds of at least 119 km/hr or 74 mph;

usually occur in late summer, early fall

Lose energy when they travel over land

very LOWLOW pressure system

Hurricane

Eye: extremely low pressure center of the

hurricane; air sinks here, so no clouds & very calm

Eye wall: ring of violent thunderstorms around the

eye; strongest wind & rain are hereeye; strongest wind & rain are here

Hurricane

Storm surge: large wave of water caused by a low-pressure system

High winds create large waves to damage High winds create large waves to damage coast & cause flooding

Worst damage happens to right of hurricane in N hemp, because wind blows counterclockwise around the low, so the strongest winds are on the right

Saffir/Simpson Scale

What do I do?

If there is an evacuation order, EVACUATE

IMMEDIATELY!

Cover windows with plywood to protect

them from flying debristhem from flying debris

Secure all outside furniture

Danger is in high winds & flooding

Beware of the calm at the eye. The storm

isn’t over yet!

Blizzard

storm with winds of 35mph or

more with considerable

falling or blowing snow

causing low visibilitycausing low visibility

What do I do?

If a blizzard is predicted, purchase supplies

ahead of time to last at least a week.

Once the storm starts, STAY INSIDE! You

can survive without food & melt snow for can survive without food & melt snow for

water. You cannot survive without shelter.

Don’t go outside for any reason. Visibility is

often so low you’ll get lost between your front

door & the car.

Nor’easter

low pressure system along East coast that blows strong that blows strong

winds from the northeast; not cold

enough for a blizzard, but very strong winds &

damage

Human Effect on Climate &

Atmosphere

Climate & Human Activities

DECEMBERMARCHJUNE

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