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Update
September 11, 2008
As we all know, a severe thunderstorm with
straight line winds of 70 mph or greater can do as much damage as a weak
(EF0) tornado.
Effective immediately, Oakland County Emergency
Response and Preparedness will activate the County's Outdoor Warning sirens
for tornados and severe thunderstorms with damaging winds at/near 70 mph or
greater in Oakland County and within a ten mile buffer around the County
(this will give citizens living close to the border more time to take
cover).
In the past,
the outdoor warning sirens were only activated when a tornado was sighted or
strongly indicated on radar. This change in policy is a result of the
tornado touchdown in Holly last year and the severe thunderstorm with
damaging 80mph winds in early June.
This doesn't mean that the
sirens will go off every time severe weather is in the area. Had the 70 mph
policy been in place, Oakland County would have activated the outdoor
warning sirens an additional 6 times since January 2006.
If you have any questions,
please call Tricia Smith, Emergency Management Supervisor, at
smitht@oakgov.com or 248 858-5371.
Michael R. Sturm, Administrator
Oakland County
Emergency Response and Preparedness |
Tornados
Thunderstorms
Lightning
Floods
Tornados
1. What is a tornado?
It is a column of violently rotating winds extending down
from a thunderstorm cloud and touching the surface of the
earth.
2. What is the difference between a tornado and a funnel
cloud?
A funnel cloud is also a column of violently rotating
winds extending down from a thunderstorm; however, it does not
touch the earth.
3. How many tornadoes usually occur in Michigan every
year?
An average of 16 tornadoes occurs in Michigan each year.
Since 1950, 239 persons have been killed due to tornadoes.
During this same time, Michigan has experienced 830 tornadoes.
4. When do tornadoes generally occur?
Most tornadoes occur during the months of June, July and
August in the late afternoon and evening hours. However,
tornadoes can occur anytime of the day or night in almost any
month during the year.
5. How fast do tornadoes travel?
Tornadoes generally travel from the southwest and at an
average speed of 30 miles per hour. However, some tornadoes
have very erratic paths, with speeds approaching 70 mph.
6. How far do tornadoes travel once they touch the
ground?
The average Michigan tornado is on the ground for less
than ten minutes and travels a distance of about five miles.
However, they do not always follow the norm, and have been
known to stay on the ground for more than an hour and travel
more than 100 miles.
7. What is a tornado watch?
A tornado/severe thunderstorm watch is issued whenever
conditions exist for severe weather to develop. Watches are
usually for large areas about two-thirds the size of lower
Michigan and are usually two-to-six hours long. Watches give
you time to plan and prepare.
8. What is a tornado warning?
The local Weather Service (NWS) office issues a tornado
warning whenever a tornado has been sighted or NWS Doppler
Radar indicates a thunderstorm capable of producing a tornado.
A severe thunderstorm warning is issued whenever a severe
thunderstorm is observed or NWS Doppler Radar indicates a
thunderstorm capable of producing damaging winds or large
hail. Warnings are for smaller areas, such as counties, and
are usually 30 minutes to one hour in length. You must act
immediately when you first hear the warning. If severe weather
is reported near you, seek shelter immediately. If not, keep a
constant lookout for severe weather and stay near a shelter.
9. How do I find out about a warning if my electricity
is already out?
In some areas, civil emergency sirens will be your first
official warning. In addition, if your television or radio has
battery back-up capability, you may receive National Weather
Service warnings from local media.
Preparing for a tornado:
- Have emergency supplies on hand, including a
battery-operated radio, a flashlight and a supply of fresh
batteries.
- Know the location of designated shelter areas in
public facilities, such as schools, shopping centers and
other public buildings.
- Make an inventory of household furnishings and other
possessions. Supplement it with photographs of each room.
Keep in a safe place.
- Plan ahead. Be sure everyone in your household knows
where to go and what to do in case of a tornado warning.
What to do when a tornado threatens:
- Get into a shelter, preferably a permanent structure,
in the basement or lowest floor.
- Stay away from windows, doors and outside walls.
Protect your head with a pillow, blankets, or even a
mattress.
- In homes and small buildings, go to the basement and
get under something sturdy. If no basement is available,
go to an interior part of home of the lowest level. A good
rule of thumb is to put as many walls between you and the
tornado as possible.
- In schools, hospitals and public places, move to
designated shelter areas. Interior hallways on the lowest
floors are best.
- Mobile homes and vehicles offer virtually no shelter.
Leave them and go to the nearest shelter. If there is no
shelter nearby, the best alternative is to lie in the
nearest ditch and shield your head with your arms.
After a tornado:
- Inspect your property, including motor vehicles for
damage. Check for electrical problems and gas leaks and
report them to the utility company at once.
- Watch out for fallen power lines. Stay out of damaged
buildings until you are sure they are safe and will not
collapse. Secure your property from further damage or
theft.
- Use only approved or chlorinated supplies of drinking
water. Check food supplies.
Anytime:
- Listen for NOAA Weather Radio, or local radio,
television and cable stations for the latest weather
updates. To insure a continuous flow of weather
information, make sure the NOAA Weather Radio, or another
radio or television has a battery back up.
- For NOAA Weather Radio information, including a
station near you,
click here to visit the NOAA Weather Radio page. The
National Weather Service, American Red Cross and Federal
Emergency Management Agency produce these publications.
Thunderstorms
What to do when thunderstorms approach:
- Move to a sturdy building.
- If too far from shelter, find a low spot away from
trees, fences and poles, but not in a place subject to
flooding. If you are boating or swimming, get to land and
shelter immediately.
- If you feel your skin tingle or hair stand on end,
lightning may be about to strike. Squat low to the ground
on the balls of your feet. Place your hands on your knees
with your head between them. Minimize contact with the
ground.
- Telephone lines and metal pipes can conduct
electricity. Unplug appliances not necessary for receiving
weather information. Use telephones only in an emergency.
Lightning
Lightning Protection
Lightning can provide a spectacular display of light on a
dark night. This awesome show of nature also causes death and
destruction. Lightning is the visible discharge of electrical
energy. It is often accompanied by thunder – which is a sonic
boom created by the same discharge. If you hear thunder,
lightning is a threat, even if the storm seems miles away and
the sky is blue. Lightning’s electrical energy seeks a path to
ground – your home, the trees in your yard or even you can be
that chosen path!
Protect Yourself
Lightning threatens much more than property. When there is
lightning nearby:
- Do not use the telephone except in an emergency.
- Stay away from electrical appliances, TVs, fireplaces,
metal objects, windows or doors.
- Seek shelter immediately in an enclosed building or
vehicle.
- Avoid isolated trees, high ground, and bodies of water
or large open areas.
What does a lightning protection system do?
A lightning protection system has two objectives:
- Provide a direct path for the lightning to follow to
ground.
- Prevent destruction, damage, injury or death as it
travels that path.
I
t is important to note that a lightning protection
system does not attract lightning. It also cannot prevent a
lightning strike; a lightning protection system does provide a
safe path to ground for the electric current.
What Does a Lightning Protection System Look Like?
Lightning
Protection Key
- Minimum of two ground rods (electrodes) at least 10 feet
deep
- Down conductors
- Connect gutters or other grounded metals as required
- Air terminals (lightning rods) located within two feet
of outside corners of chimney
- Antenna mast connected to roof conductor
- Air terminals (lightning rods) spaced 20 feet apart
along the ridges and within two feet of ridge ends
- Dormers protected
- Roof projections such as weather vanes or satellite
dishes should be connected to lightning protection system
- Surge protection devices installed at main electrical
panel or meter
- Surge protection devices installed at electronics in
house
Floods
Michigan didn’t avoid the ravages of flooding in 2002. In
fact, there was record flooding in the Upper Peninsula of
Michigan in April 2002 that caused damages in excess of $7
million.
To focus attention on flood safety planning, Governor
Jennifer Granholm has declared March 16 - 22, 2003, as "Severe
Weather Awareness Week" in Michigan. Residents are encouraged
to familiarize themselves with flood safety procedures.
During the record flooding, many local and county roads
were closed due to high water and several dams were in
jeopardy of failing. Former Governor John Engler declared a
state of emergency for Gogebic County and the county was later
declared a disaster area. In all, major flooding on rivers and
lakes occurred in eight counties of the Upper Peninsula.
According to the Michigan Committee for Severe Weather
Awareness flooding along Michigan’s rivers can occur anytime
of the year and is the result of excessive rainfall and/or the
combination of rainfall and snowmelt. Ice jams also cause
flooding in winter and early spring. Severe thunderstorms may
cause flooding during the summer or fall, although these are
normally localized and have more impact on watercourses with
smaller drainage areas. Oftentimes, flooding may not
necessarily be directly attributable to a river, stream or
lake overflowing its banks. Rather, it may simply be the
combination of excessive rainfall and/or snowmelt, saturated
or frozen ground, and inadequate drainage. With no place to
go, the water will find the lowest elevations – areas that are
often not in a floodplain. That type of flooding is becoming
increasingly prevalent in Michigan, as development outstrips
the ability of the drainage infrastructure to properly carry
and disburse the water flow. Flooding also occurs due to
combined storm and sanitary sewers that cannot handle the
tremendous flow of water that often accompanies storm events.
Typically, the result is water backing into basements, which
damages mechanical systems and can create serious public
health and safety concerns.
The Michigan Department of Environmental Quality estimates
that about 6% of Michigan’s land is flood-prone, including
about 200,000 buildings. The southern half of the Lower
Peninsula contains the areas with the most flood damage
potential. "It is not just the southern half of the Lower
Peninsula of Michigan that needs to be concerned with
flooding, flooding can occur at anytime and anywhere in
Michigan," said Mark Walton, a member of the Committee. "For
example, in the Upper Peninsula of Michigan, record setting
snowfall in February and March set the stage for spring floods
in 2002 and resulted in record flooding in April." The
Michigan State Police Emergency Management Division estimates
that Michigan’s annual flood-related damages are between $60
and $100 million.
Residents should be aware that regular homeowners'
insurance policies do not cover damages that result from
flooding. Coverage is available through a federal program;
however, in Michigan only about 15% of structures subject to
flooding are actually insured against the risk.
Currently there are approximately 769 Michigan communities
participating in the National Flood Insurance Program (NFIP)
and over 25,000 policies in force with coverage in excess of
$2.5 billion. To purchase flood insurance under the program,
residents must live in one of the participating communities.
Coverage can be obtained through most licensed
property/casualty insurance agents. To determine if flood
insurance is available in a community, call NFIP at
800.638.6620.
Under the NFIP, a flood is defined in part, as a general
and temporary condition of partial or complete inundation of
normally dry land areas from overflow of inland or tidal
waters or from the unusual and rapid accumulation of runoff of
surface waters from any source. It is important to note that
this flood definition would cover general street flooding that
was coming into a home, it does not have to come from a river.
In the standard flood insurance policy, direct physical losses
by "flood" are covered. Also covered are losses resulting from
erosion caused by waves or currents of water exceeding
anticipated cyclical levels or erosion accompanied by a severe
storm, flash flood, abnormal tidal surge, or the like.
Basement flooding is a covered hazard under the NFIP policy,
however homeowners should be aware that personal property is
not covered in a basement location.
Losses from water seepage, sewer backup, or hydrostatic
pressure are covered only when they occur in conjunction with
a general condition of flooding. In addition to obtaining
adequate insurance protection, residents should take the
following precautions in anticipation of flooding:
- Learn the best route from your home or place of
business to high, safe ground in case you have to evacuate
in a hurry.
- Prepare and maintain a list of personal property to
substantiate losses covered by insurance.
- Familiarize household members with turn-off procedures
for gas and electricity.
What is a flood and when do most occur?
A flood is the inundation of a normally dry area caused by an
increased water level in an established watercourse, such as a
river, stream, or drainage ditch, or ponding of water at or
near the point where the rain fell. Flood can occur anytime
during the year. However, many occur seasonally after winter
snow melts or heavy spring rains.
What are flash floods?
Flash floods occur suddenly, usually within six hours of
the rain event, and result from heavy localized rainfall.
Flash floods can begin before the rain stops. Water level on
small streams may rise quickly in heavy rainstorms, especially
near the headwaters of river basins. Heavy rains can also
cause flash flooding in areas where the floodplain has been
urbanized.
What are other causes of flooding in Michigan?
Ice jams and dam failures can also cause both flooding and
flash flooding.
Are people killed as a result of floods?
Many people are killed by flash floods when driving or
walking on roads and bridges that are covered by water. In
fact, flash floods are the number one weather-related killer
in the United States. Even 6 inches of fast-moving flood water
can knock you off your feet, and a depth of only two feet of
water will float many of today's automobiles. If you are in a
car and water starts rising, get out and move to higher
ground.
What is a flood watch?
A flood watch indicates that flash flooding or flooding is
possible within the designated WATCH area - be alert. It is
issued to inform the public and cooperating agencies that
current and developing weather conditions are such that there
is a threat of flooding, but the occurrence is neither certain
or imminent.
What is a flash flood or flood warning?
A flash flood or flood warning indicates that flash
flooding or flooding is already occurring or imminent within
the designated WARNING area - take necessary precautions at
once. When a flash flood or flood warning is issued for your
area, act quickly. Get out of areas subject to flooding and
avoid areas where flooding has already occurred.
What is a flash flood or flood statement?
A flash flood or flood statement is used for follow-up
information regarding a flash flood or flood event.
Preparing for a flood:
- Make an itemized list of personal property well in
advance of a flood occurring. Photograph the interior and
exterior of your home. Store the list, photos and
documents in a safe place.
- Memorize the safest and fastest route to high ground.
Assemble a disaster supplies kit containing: first aid
kit, canned food and can opener, bottled water, extra
clothing, rubber boots and gloves, NOAA Weather Radio,
battery-operated radio, emergency cooking equipment,
flashlight and extra batteries.
- If you live in a frequently flooded area, keep
sandbags, plastic sheets and lumber on hand to protect
property. Install check valves in building sewer traps to
prevent flood water from backing up into the drains of
your home.
- Know the elevation of your property in relation to
nearby streams and other waterways, and plan what you will
do and where you will go in a flood emergency.
When a flood threatens:
- If forced to leave your property and time permits,
move essential items to safe ground, fill tanks to keep
them from floating away and grease immovable machinery.
- Store a supply of drinking water in clean bathtubs and
in large containers.
- Get out of areas subject to flooding. This includes
dips, low spots, flood plains, etc.
During a flood:
- Avoid areas subject to sudden flooding.
- Even 6 inches of fast moving floodwater can knock you
off your feet, and a depth of two feet will float your
car! Never try to walk, swim or drive through such swift
water.
- Do not attempt to drive over a flooded road. STOP!
Turn around and go another way.
- Keep children from playing in floodwaters or near
culverts and storm drains.
After a flood:
- Boil drinking water before using. If fresh food has
come in contact with floodwaters, throw it out.
- Seek necessary medical care at the nearest hospital.
Food, clothing, shelter and first aid are available at Red
Cross shelters.
- Use flashlights, not lanterns or torches, to examine
buildings. Flammables may be inside.
- Do not handle live electrical equipment in wet areas.
Electrical equipment should be checked and dried before
being returned to service.
Information from the Michigan Committee for
Severe Weather Awareness
