Weather Lingo: Wind Chill

Temperature is one of the basic elements of weather.  Our perception of it, however, is often influenced by other environmental conditions. Wind, for example, can make a cold day feel even colder. This phenomenon is called the wind chill factor.

Wind chill is a measure of the apparent or “feels-like” temperature.  It calculates the heat loss from exposed human skin through the combined effects of air temperature and wind speed.

Essentially, the wind is carrying heat away from the body and allowing the skin to be exposed to cold air.  As the winds increase, heat is carried away at a faster rate and the colder the body feels.  For example, a temperature of 20°F and a wind speed of 5mph will produce a wind chill index of 13°F.  At that same temperature, but with a wind speed of 10mph, the wind chill index would be 9°F.

Extended exposure to low wind chill values can lead to frostbite and hypothermia, serious winter health hazards.

Extremely Cold Weather Can Be A Danger to Your Health

An arctic blast is expected to sweep across the northeastern United States this week. With temperatures expected to fall into the single digits, 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:

There is No Such Thing as Bad Weather, Only Bad Clothing Choices

There is an old Scandinavian saying: “There is no such thing as bad weather, only bad clothing choices.” While it can be applied to any season, it seems most relevant in winter.

Since the weather is going to do whatever it is going to do, it is important to be prepared for anything that Mother Nature throws your way. In winter, that means cold temperatures.

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 such as hypothermia and frostbite.

To stay safe this winter, remember to bundle up in layers and wear hats and gloves to minimize the loss of body heat.

Credit: NOAA

The Deadly Danger of Lightning

Thunderstorms are impressive displays of the power of nature. However, they are also extremely dangerous.

On average, according to NOAA, lightning claims the lives of 47 people every year in the US and seriously injures hundreds more. To date in 2018, lightning has killed 16 people across eight states. The most recent victim was struck this Saturday at Sunken Meadows State Park on Long Island, NY. Local officials say the man was sheltering under a tree during an early evening storm.

Lightning comes in variety of forms, but the cloud to ground variety is the most threatening to people. A typical bolt carries a current of about 300 million volts and can heat the air around it to 50,000°F. That is five times hotter than the surface of the sun.

This type of lightning, NOAA says, strikes the US about 25 million times a year. However, 70% of lightning fatalities occur during the summer months. The season marks not only the peak of thunderstorm activity in the US, but also the time of year when people spend more time outdoors.

Top ten activities that contributed the most to lightning deaths in the US, 2006-2017. Credit: NWS

According to a NWS report on lightning deaths in the US from 2006 to 2017, the vast majority of victims were men engaged in an outdoor leisure activity. Listing a variety of different pastimes at the time they were struck, fishing topped the list as the most deadly. It accounted for nearly 10% of the lightning fatalities during that period.

To avoid becoming a statistic, follow the advice of the NWS – “When thunder roars, go indoors.”

Credit: NWS/NOAA

Weather and Health: Hot Car Deaths

Summer weather can pose a number of health and safety concerns, from poor air quality to being hit by lightning. One of the more deadly risks for children, however, is heatstroke when they are left in a hot car.

Since 1998, according to kidsandcars.org, there has been an average of 37 hot car deaths in the US every year. That is one every nine days. This year, there have already been 34 deaths reported.

Credit: USA Today

On a sunny day, the interior temperature of a parked car can increase 19°F in just ten minutes. That means if the outside air temperature is a seemingly comfortable 70°F, the inside of the car can heat up to near 90°F in a very short period. The situation is even worse when the outside temperature is higher and the car sits in the sun longer.

According to the Mayo Clinic, if the human body reaches 104°F, organ damage and death become a real risk. Children are even more vulnerable because their smaller bodies can heat up between three to five times faster than that of an adult. Most hot car victims are under the age of three.

These dangerous situations develop in a number of different ways. Children can sometimes find their own way into a car while playing outside or a guardian leaves them alone in a vehicle for what seems like a quick errand. However, the majority of hot car deaths occur when a parent or caregiver gets distracted or has a change in their daily routine and simply forgets that a child is in the back seat when they park their car.

To avoid a heartbreaking tragedy, remember to Look Before You Lock!

NoHeatstroke.org

Weather and Health: Air Quality

The air we breathe is not always good for us. It often contains pollution, which can cause or aggravate a number of health issues including respiratory and cardiovascular diseases.

Under the Clean Air Act, the EPA is responsible for monitoring air pollution across the United States. Calculated on the Air Quality Index (AQI), a standardized indicator, the agency’s daily reports focus on the health effects people may suffer as a result of breathing polluted air. The scale runs from 0-500 with increasing AQI values correlating to higher levels of pollution and an escalating risk to public health. Values above 100 are considered unhealthy.

Unlike some other environmental challenges, air pollution is nearly impossible to avoid, as we all need to breathe. Caused mainly by vehicle exhaust, power generation, and industrial emissions, its sources are ubiquitous. The five major air pollutants measured on the AQI are, ground level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide.

Pollutants often build to unsafe concentrations on days with very high temperatures and/or a lack of wind.  Ground level ozone, for example, forms when nitrogen oxides react with heat and U.V. light near the surface. Air quality alerts, therefore, are often issued in conjunction with heat advisories.

Weather Lingo: Humidity

“It’s not the heat, it’s the humidity.” This old adage heard throughout much of the summer in the eastern US, refers to how the amount of water vapor in the air affects human comfort. Since the body’s main source of cooling is evaporation of perspiration, the more moisture there is in the air, the less evaporation takes place and the warmer we feel. Two ways to indicate atmospheric moisture content are relative humidity and the dew point temperature.

Relative humidity (RH) measures the actual amount of moisture in the air compared to the total amount of moisture that the air can hold. It is expressed as a percentage and is commonly used in generic weather reports and apps. A high RH can produce fog and a low RH can cause rapid dehydration in both people and plants – important information for some sectors such farmers and crews fighting wildfires. But, since warm air can hold more moisture than cool air, the relative humidity changes as the air temperature changes.

The dew point temperature, on the other hand, is an absolute measurement and is often the preferred metric of meteorologists. It is the temperature to which air must be cooled in order to reach saturation. In other words, when the air temperature and the dew point temperature are same, the air is saturated and the relative humidity is 100%. If the air were to cool further, the water vapor would condense into liquid water, such as dew or precipitation.

The classic example of this phenomenon is a glass of cold liquid sitting on a table outside on a warm, muggy day. The beverage cools the air around it and beads of water form on the outside of the glass. The temperature at which the beads of water form is the dew point.

Simply put, the closer the dew point temperature is to the air temperature, the more humid it feels. In summer, when the air is warm and can hold a lot of moisture, a dew point temperature in the 50s is generally considered comfortable. Dew points in the 60s are thought of as muggy and once they reach the 70s or higher, the air can feel oppressive. On the opposite end of the spectrum, dew points in the 40s or lower are considered dry, and dry air has its own set of comfort issues

What is a Rip Current and Why is it Dangerous?

Summer vacation season is in full swing across the US. As millions of people head to beaches to have fun and 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 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 speeds 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 area also usually appears 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

Credit: NOAA

Weather Lingo: Heat Index

Temperature is one of the basic elements of weather.  Our perception of it, however, is often influenced by other factors.  In summer, this is usually humidity.

The heat index, developed in the late 1970’s, is a measure of the apparent or “real feel” temperature when heat and humidity are combined.  Since the human body relies on the evaporation of perspiration to cool itself, the moisture content of the air affects comfort levels. Basically, as humidity levels increase, the rate of evaporation decreases and the body can begin to feel overheated.  For example, an air temperature of 92°F combined with a relative humidity level of 60% will produce a heat index value of 105°F.

The National Weather Service issues heat advisories when the heat index is forecast to be at least 95°F for two consecutive days or 100°F for any length of time.  Extended exposure to high heat index values can lead to serious health hazards.

Heat-Index

Credit: NOAA

Volcanic Smog: Kilauea’s Other Threat

Lava is not the only thing flowing out of the fissures of Kilauea on Hawaii. Sulfur dioxide, a foul-smelling and toxic gas, has also driven people from their homes.

According to the USGS, sulfur dioxide levels near the volcano have been measured above 100 parts per million. That is a level considered dangerous to human health. Noxious on its own, sulfur dioxide is also the main ingredient in volcanic smog. Known as vog in Hawaii, it can have a variety of adverse health effects.

Vog occurs when the sulfur dioxide spewing from a volcano reacts with oxygen, moisture, and other particles in the air in the presence of sunlight. It is considered a form of air pollution, not unlike that given off by power plants burning sulfurous coal. Looking back to December 1948, a similar type of toxic smog caused by unregulated industrial pollution killed 26 people and sickened thousands of others in Donora, PA.

Volcanic smog can irritate the skin, eyes, nose, throat, and lungs. Shortness of breath and dizziness can also occur.  Its effects can be even worse for anyone with respiratory problems or lung disease.

This threat, on top of the flowing lava, has led public health officials to order an evacuation of areas around the fissures, such as the hard hit Leilani Estates.  Other parts of the Big Island, however, have reported moderate to good air quality. This is largely because the region’s prevailing northeast trade winds have been pushing the vog offshore. If those winds slacken and a southeasterly flow emerges, the vog could impact a wider area, including other islands in the Hawaiian chain.

Volcanic eruptions spew gas as well as lava. Credit: GoVisitHawaii