Flash floods, isolated tornados through Friday
With a Tropical Storm warning and a Flash Flood Watch for the region through Friday, South Carolina has most certainly entered hurricane season.
The National Weather Service has issued a Tropical Storm Warning for the coastal region with Flash Flood watches inland. The NWS also warns of the increased potential for tornadoes through Friday as Andrea, the first named storm of the hurricane season takes aim at the east coast.
Mario Formisano, director of Dorchester County Emergency Management, says his department is very busy anticipating where problems might occur and its response.
“Our primary concern as of right now,” he said Thursday morning, “is localized flooding. We are in a heightened state of readiness and monitoring the situation.”
Formisano said Thursday morning that between midnight Thursday and early morning Friday is when they expect the greatest amount of impact. “This is definitely an event.”
Formisano noted that there is always a “cone of error” in predicting paths of storms, which can be a wide as 120 miles.
“The low lying areas are of most concern,” he said., and that conditions can change very quickly.
Formisano said the timing between rainfalls is key to flooding.
As of Thursday morning, Dorchester Road at Orangeburg Road was closed because of flooding, according to the SC Highway Patrol traffic information site.
Living in a region for which severe weather is part of the seasonal expectation can sometimes cause complacency. That's when it gets dangerous.
“You can't get caught up in 'it's just a tropical storm,'” he said.
Formisano expects a significant amount of rain and the possibility of isolated tornado activity. “Not your typical tornado activity like what happened over the last couple of days,” he said.
Staying alert and respectful of the weather and being prepared are the best ways to protect yourself and your family.
You can receive important lifesaving alerts no matter where you are – at home, school or work.
Wireless Emergency Alerts (WEA) send free informational text messages to WEA-enabled cell phones within range of an imminent and dangerous local situation, severe weather event, or AMBER emergency.
You do not need to register to receive WEA notifications. You will automatically receive alerts if you have WEA-capable phone and your wireless carrier participates in the program.
Plan for risks
Local Emergency management offices can help identify the hazards in your area and outline the local plans and recommendations for each. Formisano recommends going to www.ready.gov, which is what they use, he said, to help prepare the public. The website offers clear and simple instruction for dealing with most any disaster possibly including:
All thunderstorms are dangerous. Lightning continues to be one of the top three storm-related killers in the United States.
Other associated dangers of thunderstorms include tornadoes, strong winds, hail and flash flooding. Flash flooding is responsible for more fatalities – more than 140 annually – than any other thunderstorm-associated hazard.
Before a Flood
Flood risk isn't just based on history; it's also based on a number of factors including rainfall, topography, flood-control measures, river-flow and tidal-surge data, and changes due to new construction and development.
To prepare for a flood, you should:
• Build an emergency kit and make a family communications plan.
• Avoid building in a floodplain unless you elevate and reinforce your home.
• Elevate the furnace, water heater and electric panel in your home if you live in an area that has a high flood risk.
• Consider installing "check valves" to prevent floodwater from backing up into the drains of your home.
Tropical Storms and Hurricanes
Hurricanes pack a triple punch: high winds, soaking rain, and flying debris. They can cause storm surges to coastal areas, as well as create heavy rainfall, which in turn causes flooding hundreds of miles inland.
When hurricanes weaken into tropical storms, they generate rainfall and flooding that can be especially damaging since the rain collects in one place.
Heavy Rains - Several areas of the country are at heightened risk for flooding due to heavy rains. The Northwest is at high risk due to La Niña conditions, which include snowmelts and heavy rains. And the Northeast is at high risk due to heavy rains produced from Nor'easters. This excessive amount of rainfall can happen throughout the year, putting your property at risk.
Flash Floods - Flash floods are the #1 weather-related killer in the U.S. since they can roll boulders, tear out trees, and destroy buildings and bridges. A flash flood is a rapid flooding of low-lying areas in less than six hours, which is caused by intense rainfall from a thunderstorm or several thunderstorms. Flash floods can also occur from the collapse of a man-made structure or ice dam.
New Development - Construction and development can change the natural drainage and create brand new flood risks. That's because new buildings, parking lots, and roads mean less land to absorb excess precipitation from heavy rains, hurricanes, and tropical storms.
Familiarize yourself with these terms to help identify a flood hazard:
Flood Watch - Flooding is possible. Tune in to NOAA Weather Radio, commercial radio or television for information.
Flash Flood Watch - Flash flooding is possible. Be prepared to move to higher ground; listen to NOAA Weather Radio, commercial radio or television for information.
Flood Warning - Flooding is occurring or will occur soon; if advised to evacuate, do so immediately.
Flash Flood Warning - A flash flood is occurring; seek higher ground on foot immediately.
The following are important points to remember when driving in flood conditions:
• Six inches of water will reach the bottom of most passenger cars causing loss of control and possible stalling.
• A foot of water will float many vehicles
• Two feet of rushing water can carry away most vehicles including sport utility vehicles (SUV's) and pick-ups.
• Do not attempt to drive through a flooded road. The depth of water is not always obvious. The roadbed may be washed out under the water, and you could be stranded or trapped.
• Do not drive around a barricade. Barricades are there for your protection. Turn around and go the other way.
• Do not try to take short cuts. They may be blocked. Stick to designated evacuation routes.
• Be especially cautious driving at night when it is harder to recognize flood dangers.
During a Flood
If a flood is likely in your area, you should:
• Listen to the radio or television for information.
• Be aware that flash flooding can occur. If there is any possibility of a flash flood, move immediately to higher ground. Do not wait for instructions to move.
• Be aware of stream, drainage channels, canyons and other areas known to flood suddenly. Flash floods can occur in these areas with or without typical warnings such as rain clouds or heavy rain.
• If you must prepare to evacuate, you should do the following:
• Secure your home. If you have time, bring in outdoor furniture. Move essential items to an upper floor.
• Turn off utilities at the main switches or valves if instructed to do so. Disconnect electrical appliances. Do not touch electrical equipment if you are wet or standing in water.
If you have to leave your home, remember these evacuation tips:
• Do not walk through moving water. Six inches of moving water can make you fall. If you have to walk in water, walk where the water is not moving. Use a stick to check the firmness of the ground in front of you.
• Do not drive into flooded areas. If floodwaters rise around your car, abandon the car and move to higher ground if you can do so safely. You and the vehicle can be swept away quickly.
• Do not camp or park your vehicle along streams, rivers or creeks, particularly during threatening conditions.
Tornadoes are nature's most violent storms. Spawned from powerful thunderstorms, tornadoes can cause fatalities and devastate a neighborhood in seconds. A tornado appears as a rotating, funnel-shaped cloud that extends from a thunderstorm to the ground with whirling winds that can reach 300 miles per hour.
Damage paths can be in excess of one mile wide and 50 miles long. Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others.
Occasionally, tornadoes develop so rapidly that little, if any, advance warning is possible. Before a tornado hits, the wind may die down and the air may become very still. A cloud of debris can mark the location of a tornado even if a funnel is not visible.
Tornadoes generally occur near the trailing edge of a thunderstorm. It is not uncommon to see clear, sunlit skies behind a tornado.
Before a Tornado
To begin preparing, you should build an emergency kit and make a family communications plan.
Listen to NOAA Weather Radio or to commercial radio or television newscasts for the latest information. In any emergency, always listen to the instructions given by local emergency management officials.
Be alert to changing weather conditions. Look for approaching storms.
Look for the following danger signs:
• Dark, often greenish sky
• Large hail
• A large, dark, low-lying cloud (particularly if rotating)
• Loud roar, similar to a freight train.
If you see approaching storms or any of the danger signs, be prepared to take shelter immediately.
Quick facts you should know about tornadoes:
• They may strike quickly, with little or no warning.
• They may appear nearly transparent until dust and debris are picked up or a cloud forms in the funnel.
• The average tornado moves southwest to Northeast, but tornadoes have been known to move in any direction.
• The average forward speed of a tornado is 30 mph, but may vary from stationary to 70 mph.
• Tornadoes can accompany tropical storms and hurricanes as they move onto land.
• Waterspouts are tornadoes that form over water.
• Peak tornado season in the southern states is March through May; in the northern states, it is late spring through early summer.
• Tornadoes are most likely to occur between 3 pm and 9 pm, but can occur at any time.
Familiarize yourself with these terms to help identify a tornado hazard:
Tornado Watch - Tornadoes are possible. Remain alert for approaching storms. Watch the sky and stay tuned to NOAA Weather Radio, commercial radio or television for information.
Tornado Warning - A tornado has been sighted or indicated by weather radar. Take shelter immediately.
During a Tornado
If you are under a tornado warning, seek shelter immediately! Most injuries associated with high winds are from flying debris, so remember to protect your head.
If you are in:
A structure (e.g. residence, small building, school, nursing home, hospital, factory, shopping center, high-rise building)
Go to a pre-designated shelter area such as a safe room, basement, storm cellar, or the lowest building level. If there is no basement, go to the center of an interior room on the lowest level (closet, interior hallway) away from corners, windows, doors, and outside walls. Put as many walls as possible between you and the outside. Get under a sturdy table and use your arms to protect your head and neck.
In a high-rise building, go to a small interior room or hallway on the lowest floor possible.
Put on sturdy shoes.
Do not open windows.
A trailer or mobile home
Get out immediately and go to the lowest floor of a sturdy, nearby building or a storm shelter. Mobile homes, even if tied down, offer little protection from tornadoes.
The outside with no shelter
Immediately get into a vehicle, buckle your seat belt and try to drive to the closest sturdy shelter.
If your vehicle is hit by flying debris while you are driving, pull over and park.
Stay in the car with the seat belt on. Put your head down below the windows; cover your head with your hands and a blanket, coat or other cushion if possible.
If you can safely get noticeably lower than the level of the roadway, leave your car and lie in that area, covering your head with your hands
Do not get under an overpass or bridge. You are safer in a low, flat location.
Never try to outrun a tornado in urban or congested areas in a car or truck. Instead, leave the vehicle immediately for safe shelter.
Watch out for flying debris. Flying debris from tornadoes causes most fatalities and injuries.