National Weather Service Says to Expect Coastal Flooding with Rain and Tidal Anomaly
The National Weather Service has issued a coastal flood advisory in effect until 1 a.m. Friday. The advisory will be higher during high tides on Thursday morning and evening. The advisory is in effect for Anne Arundel, Calvert and St. Marys counties.
In our area, high tides will be at:
- 9:09 a.m. and 10:21 p.m. for the South River,
- 9:16 a.m. and 10:24 p.m. for Shady Side/West River, and
- 9:22 a.m. and 10:44 p.m. for the US Naval Academy
NWS said a Coastal Flood Advisory indicates that onshore winds and tides will combine to generate flooding of low areas along the shore. Expect a tidal anomaly of one to one-and-a-half feet above normal. Take precautions if you live in low-lying areas.
Also be aware that there may be road closures for low-lying roadways in South County as the day wears on and the rain continues to fall. Please do not drive into standing water!
Nearly every time we have a heavy rainfall and coastal flood advisories, we have fire and emergency workers conducting swift water rescues. Please don’t be one of these stories. Not only is it scary, but the time you had hoped to save by not driving around another way will be entirely lost—and you won’t have a car at the end of it.
Last October, I posted this item; I’m re-posting it as a reminder to drivers. Please read:
‘Turn Around, Don’t Drown’
Driving into flood waters is so common that the National Weather Service (NWS), the National Oceanographic and Atmospheric Administration (NOAA), and the Centers for Disease Control (CDC) have a campaign, “Turn Around, Don’t Drown,” where they urge drivers to heed flood warnings, road closures and barricades.
The CDC reports that up to half of flood deaths occur when people drive their cars into hazardous flood waters. The CDC said that the next highest percentage of flood-related deaths is from people walking into or near swift-moving flood waters.
NOAA’s report said that many people believe their 3,000 pound vehicle will keep them safe. It doesn’t. That is because all those pounds can’t overcome buoyancy, or the tendency of a fluid (water) to exert an upward force on a body (your car) submerged in it.
It’s plain old physics.
If you think about it, we all know that heavy things can float. An aircraft carrier, nearly 100,000 tons floats as do cargo ships. Both are heavy but perfectly buoyant.
So then, what happens to a car in flood waters? First, the car is lifted by buoyancy. In just 6 to 8 inches of floodwater, buoyancy begins to eliminate the friction that brakes need in order to work. For each foot in water depth, a car displaces about 1,500 pounds of water. So by two feet, your 3,000-pound car is now a boat. Albeit a boat that can’t steer and is at the mercy of the current, which, during storms and flash flooding, can move swiftly.
So, the next time you have the urge to “save time” by ignoring road closures and flood waters—turn around. Don’t drown.
Stay safe out there South Countians!