Tag Archives: safety

Rip Current Awareness for the Summer Beach Season

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Summer vacation season has arrived and millions of people will be heading to beaches to beat the heat over the next few months. As such, it is important to remember that the ocean is a dynamic environment that can pose a number of hazards for swimmers.  Chief among these are rip currents.

Rip currents are fast, localized channels of water moving away from the shoreline. According to NOAA, they are a result of “complex interactions between waves, currents, water levels and nearshore bathymetry.” They can form in several different ways on any beach with breaking waves. That said, they are typically found at breaks in sandbars and along permanent structures that extend out into the water such as jetties or piers.

Moving at up to 8 feet per second – which is faster than an Olympic swimmer – rip currents can easily drag unsuspecting swimmers hundreds of yards out to sea.  While they will not pull anyone underwater, they can cause fatigue and panic. According to the U.S. Lifesaving Association, rip currents are responsible for 80% of all surf zone rescues. Nationally, they cause more than one hundred deaths every year.

To spot a rip current, look for a gap in the breaking waves.  This is where the water is forcing its way back out to sea.  The water in this area is also usually murky and darker than the surrounding water.  On guarded beaches, red flags indicate hazardous conditions for swimmers.

If caught in a rip current, the Red Cross recommends not trying to swim against it.  Instead, they say to swim parallel to the shoreline until you are out of the current. Once free, you can start swimming back toward the beach.

For more information on beach safety, visit: http://www.redcross.org/prepare/disaster/water-safety/beach-safety

rip-current

Image Credit: NOAA.

How Thunder and Lightning Form

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Flash! Bang! Thunderstorms are impressive displays of the power of nature. But how, you may wonder, do lightning and thunder form?

First comes the lightning, an intense electrical discharge. While not completely understood, it is believed to form as a result of the separation of charges within a cumulonimbus cloud.  One theory of how this happens involves the collision of particles within these towering clouds, including hailstones, super-cooled liquid water droplets, and ice crystals.  When they mix and collide, according to NOAA, “electrons are sheared off the ascending particles and collect on the descending particles.” This results in a cloud with a negatively charged base and a positively charged top.

As the atmosphere is a good insulator, generally inhibiting the flow of electricity, the strength of this electrical field has to build up substantially before lightning can occur. Most discharges, about 75%, occur across the electrical field within the storm cloud itself. This is known as intra-cloud lightning.

Another electrical field can also develop below the cloud. Since the cloud base is negatively charged, it induces a positive charge on the ground below, especially in tall objects such as buildings and trees. When the charge separation becomes large enough, a negatively charged stepped leader – an invisible channel of ionized air, moves down from the base of the cloud. When it meets a channel of positive charges reaching up from the ground, known as a streamer, a visible flash of lightning can be seen.  This is called cloud to ground lightning.

Lightning can be as hot as 54,000°F, a temperature that is five times hotter than the surface of the sun. When it occurs, it heats the air around it in a fraction of a second, creating an acoustic shock wave.  This is thunder.  A nearby lightning strike will produce thunder that sounds like a sharp crack. Thunder from a distant storm will sound more like a continuous rumble.

While thunderstorms can be spectacular events to watch, they are also very dangerous.  So, as the National Weather Service recommends, “When thunder roars, go indoors.”

Credit: NWS

Credit: NWS

Green Skies

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Thunderstorms are fairly common in the late spring and summer in the United States. Every once in a while, though, they can be severe. When they are, the sky often turns green. You may wonder, what causes this odd coloration?

According to scientists, the phenomenon of green skies is not completely understood. The leading theory, however, involves the dense moisture content of cumulonimbus clouds and the time of day. Most thunderstorms develop in the late afternoon, a time when the sun’s rays have to travel a long way through the atmosphere before reaching the ground. This causes the light we see around sunset to be reddish-yellow. Thunderstorm clouds contain large amounts of rain and hail. This water and ice scatters blue light. So, when these towering clouds form in the late afternoon, the two colors mix to give the sky a green or blue-green appearance.

While severe thunderstorms can produce tornadoes, a green sky does not necessarily mean a twister is coming. Nonetheless, the color is associated with dangerous weather. If you see a thunderstorm heading your direction and the sky appears green, you should seek shelter immediately.

Green Sky. Image Credit: Sky7WX

Green Sky.   Image Credit: Sky7WX

Weather and Health: Extreme Cold

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Persistent frigid temperatures have been gripping a large part of the United States recently.  In these conditions it is important to remember that, like extreme heat, extreme cold can be very dangerous.

Extreme cold causes the body to lose heat faster than it can be generated.  Prolonged exposure, according to the CDC, can cause serious health problems, including hypothermia and frostbite.

Hypothermia is a condition of unusually low body temperature – generally below 95°F.  It impairs brain functions, limiting a victim’s ability to think and move.  Symptoms include severe shivering, drowsiness, confusion, slurred speech, and fumbling.  If left untreated, it can be fatal.

Frostbite is a localized injury to the skin and underlying tissues caused by freezing.  It can cause permanent damage and extreme cases often require amputation.  Areas of the body most often affected include the nose, ears, cheeks, fingers and toes. Signs of frostbite include, numbness, skin discoloration (white or greyish-yellow), and unusually firm or waxy feeling skin.

While the symptoms of both hypothermia and frostbite can range in severity, victims generally require immediate re-warming and professional medical attention.

To stay safe in cold weather, the American Red Cross recommends:

  • Avoiding prolonged exposure to extremely low temperatures
  • Wearing layers of clothing to keep warm
  • Using hats and gloves to minimize the loss of body heat

High Winds and the Macy’s Thanksgiving Day Parade

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The Macy’s Thanksgiving Day Parade is a long-standing holiday tradition in New York City.  This year, high winds could ground the event’s famous giant character balloons.

According to city guidelines, the multi-story balloons cannot fly if there are sustained winds in excess of 23 mph or gusts above 34 mph.  The current forecast for Thanksgiving Day expects winds close to this threshold.  Parade organizers say they will monitor the weather conditions and consult with the city on Thursday morning to decide if the balloons can fly and at what height.

While the parade marches in rain or shine, high winds are a serious threat to the massive balloons and the crowds of spectators that line the route.  In 1997, gusty winds sent the “Cat in the Hat” balloon careening into a light post, which caused debris to fall on parade goers, seriously injuring one person. Following this incident, a mayoral commission established the wind regulations currently in place.

With or without balloons, the 87th Annual Macy’s Thanksgiving Day Parade is scheduled to begin at 9 AM on Thursday morning.  Happy Thanksgiving!

“Hello Kitty” Balloon floats down Broadway as part of the Macy’s Thanksgiving Day Parade.                         Image Credit: 1000cutethings.com

NYC Updates Hurricane Evacuation Zones

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Super-storm Sandy devastated New York City last autumn.  In its wake, emergency management officials have re-drawn the city’s hurricane evacuation zones.

The new zones are based on improved data from SLOSH (sea, lake, and overland surges from Hurricanes), a national Weather Service computer model designed to estimate storm surges.  This new system takes the width of a storm and its wind field into account whereas the old zones were primarily based on a hurricane’s Saffir-Simpson category.

NYC’s new zones are labeled 1 through 6, with zone 1 being the first to be evacuated in the event of a storm.  This system is numeric to avoid confusion with FEMA’s flood zone maps used for insurance purposes.

Go to nyc.gov/hurricane to see if you live or work in an evacuation zone.

NYC's new hurricane evacuation zones.

NYC’s new hurricane evacuation zones.

Image Credit: nyc.gov

Long Duration Heat Wave in NYC

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Temperatures have been soaring in New York City. Today was our third consecutive day with temperatures in the 90s and more are on the way.

Forecasters say this heat wave – the second this month in NYC – will be of unusually long duration.  Temperatures are expected to reach the mid-90s everyday for another three to four days. Humidity levels will also remain high, making it feel even hotter.  Heat index values, which combine temperature and humidity, are projected to persist in the triple digits.

While these conditions are oppressive, they are also very dangerous.  Extended exposure can cause a number of serious health hazards.  According to the CDC, extreme heat is one of the leading causes of weather related deaths in this country.

To help people beat the heat, the city is operating cooling centers.  To find one near you, go to nyc.gov.

Rip Currents

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The dog days of summer have arrived!  As millions of people head to beaches to beat the heat, it is important to remember that the ocean is a dynamic environment that can pose a number of hazards for swimmers.  Chief among these are rip currents.

Rip currents are strong, localized channels of water that move away from the shoreline. They can form on any beach with breaking waves and easily pull swimmers out to sea in a matter of seconds.  According to the U.S. Lifesaving Association, rip currents are responsible for 80% of all surf zone rescues. Nationally, they cause more than one hundred deaths every year.

While rip currents are a serious hazard for all beach goers, they are a natural part of the near-shore ocean circulation.  They develop when wind driven waves break strongly in one area and weakly in another, creating a circulation cell as the water looks for a way back out to sea.  This usually happens at a break in an underwater sandbar or along a jetty or pier. Extending seaward for hundreds of yards, rip currents typically travel at one to two feet per second.  However, they strengthen when onshore wind speeds pick up and wave height and frequency increase.

If caught in a rip current, do not try to swim against it.  Instead, swim parallel to the shoreline until you are out of the current and then make your way back to the beach.

rip-currentImage Credit: NOAA

Preparing for Hurricane Sandy

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Hurricane Sandy, the 18th named storm of this Atlantic hurricane season, battered the Caribbean earlier this week.  Now, it is on course to make landfall along the northeastern coast of the United States within the next few days.

Forecasters, at this point, are uncertain of the exact track the storm will take, but expect it to be a long duration and high impact event. They anticipate that Sandy will bring high winds, heavy rain, coastal storm surges, and flooding to this country’s most densely populated region.  These weather hazards are, in turn, likely to cause widespread power outages.

To prepare, emergency officials suggests:

  • Monitor the news for the latest storm information and any evacuation orders
  • Prepare a storm emergency kit with:
    • Water
    • Non-perishable food
    • Flashlights
    • Battery-powered or hand-crank radio
    • First aid kit
    • Cash
    • Filled prescriptions
    • Extra batteries

For more details on storm preparedness, visit the websites of FEMA and the American Red Cross.

Weather and Health: Extreme Heat

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An oppressive heat wave is currently scorching the central region of the United States and is forecast to expand eastward this weekend.  As temperatures soar, it is important to remember that intense heat can cause serious health problems.

According to the CDC, extreme heat – temperatures that are significantly hotter than the average local summertime high – is one of the leading causes of weather related deaths in this country.   Claiming hundreds of lives every year, excessive heat kills more people across the U.S. than hurricanes, tornadoes, floods, and earthquakes combined.

Extreme heat is deadly, because it forces the human body beyond its capacity to cool itself. Linked to overheating and dehydration, heat related illnesses range in severity from mild to life threatening.  Symptoms for each stage include:

Heat Cramps:  painful muscle spasms in the legs and/or abdomen

Heat Exhaustion:  fatigue, weakness, clammy skin, and nausea

Heat Stroke:  rapid pulse, hot and dry skin, no sweating, victim could possibly be
unconscious;  a medical emergency

To beat the heat, the American Red Cross suggests:

  • Avoid strenuous activity
  • Dress lightly
  • Eat lightly
  • Drink plenty of water
  • Replenish salts and minerals lost to perspiration
  • Limit caffeine and alcohol
  • Stay out of the sun
  • Cool off in an air-conditioned building, when possible