As Lightning Awareness Week continues, today's topic is lightning safety. Below is some important safety information for when you are outside, inside, or on the water.
Safe Buildings
"A safe building is one that is fully enclosed with a roof, walls and floor, such as a home, school, office building or a shopping center. Even inside, you should take precautions. Picnic shelters, dugouts, sheds and other partially open or small structures are NOT safe."
"Enclosed buildings are safe because of wiring and plumbing. If lightning strikes these types of buildings, or an outside telephone pole, the electrical current from the flash will typically travel through the wiring or the plumbing into the ground. This is why you should stay away from showers, sinks, hot tubs, etc., and electronic equipment such as TVs, radios, and computers."
"Lightning can damage or destroy electronics so it's important to have a proper lightning protection system connected to your electronic equipment. The American Meteorological Society has tips for protecting your electronics from lightning."
Unsafe Buildings
"Examples of buildings which are unsafe include car ports, covered but open garages, covered patio, picnic shelters, beach shacks/pavilions, golf shelters, camping tents, large outdoor tents, baseball dugouts and other small buildings such as sheds and greenhouses that do not have electricity or plumbing."
Safe Vehicle
"A safe vehicle is a hard-topped car, SUV, minivan, bus, tractor, etc. (soft-topped convertibles are not safe) . If you seek shelter in your vehicle, make sure all doors are closed and windows rolled up. Do not touch any metal surfaces."
"If you're driving when a thunderstorm starts, pull off the roadway. A lightning flash hitting the vehicle could startle you and cause temporary blindness, especially at night."
"Do not use electronic devices such as HAM radios during a thunderstorm. Lightning striking the vehicle, especially the antennas, could cause serious injury if you are talking on the radio or holding the microphone at the time of the flash. Emergency officials such as police officers, firefighters, security officers, etc., should use extreme caution using radio equipment when lightning is in the area."
"Your vehicle and its electronics may be damaged if hit by lightning. Vehicles struck by lightning are known to have flat tires the next day. This occurs because the lightning punctures tiny holes in the tires. Vehicles have caught fire after being struck by lightning; however, there is no modern day documented cases of vehicles "exploding" due to a lightning flash."
When a Safe Location is Nearby:
"Seek safe shelter when you first hear thunder, see dark threatening clouds developing overhead or lightning. Count the seconds between the time you see lightning and hear the thunder.
Stay inside until 30 minutes after you last hear thunder."
"Figure: When you hear thunder, run to the nearest large building or a fully enclosed vehicle. You are not safe anywhere outside."
"Plan Ahead! Your best source of up-to-date weather information is a NOAA Weather Radio (NWR). Portable weather radios are handy for outdoor activities. If you don't have NWR, stay up to date via internet, TV, local radio or cell phone. If you are in a group, make sure all leaders or members of the group have a lightning safety plan and are ready to use it."
"Determine how far you are from a safe enclosed building or a safe vehicle. As soon as you hear thunder, see lightning or see dark threatening clouds, get to a safe location. Then wait 30 minutes after the last rumble of thunder before you leave the safe location. If you are part of a group, particularly a large one, you will need more time to get all group members to safety. NWS recommends having professional lightning detection equipment so your group can be alerted from significant distances from the event site."
"When groups are involved, the time needed to get to safety increases. So you need to start leaving sooner. Your entire group should already be in a safe location when the approaching storm reaches within 5 miles from your location."
On the Water
"The vast majority of lightning injuries and deaths on boats occur on small boats with NO cabin. It is crucial to listen to the weather on a small aquatic vessel without a cabin. If thunderstorms are forecast, don't go out. If you are out on the water and skies are threatening, get back to land and find a safe building or vehicle."
"Boats with cabins offer a safer but not perfect environment. Safety is increased further if the boat has a properly installed lightning protection system. If you are inside the cabin, stay away from metal and all electrical components. STAY OFF THE RADIO UNLESS IT IS AN ABSOLUTE EMERGENCY!"
"What should you do if you are on a small vessel and lightning becomes a threat? If the vessel has an anchor, then you should properly anchor the boat then get as low as possible."
"Large boats with cabins, especially those with lightning protection systems properly installed or metal marine vessels are relatively safe. Remember to stay inside the cabin and away from any metal surfaces."
Source: NOAA
Wednesday, June 25, 2008
Tuesday, June 24, 2008
Lightning Safety Awareness Week Part Two
Keeping with the theme of Lightning Safety Awareness Week, here are some facts from www.noaa.gov about lightning.
"Each spark of lightning can reach over five miles in length, soar to temperatures of approximately 50,000 degrees Fahrenheit, and contain 100 million electrical volts. "
"At any given moment, there are 1,800 thunderstorms in progress somewhere on the earth. This amounts to 16 million storms each year! "
"Lightning has been seen in volcanic eruptions, extremely intense forest fires, surface nuclear detonations, heavy snowstorms, and in large hurricanes, however, it is most often seen in thunderstorms."
"Ice in a cloud seems to be a key element in the development of lightning. Storms that fail to produce quantities of ice may also fail to produce lightning. In a storm, the ice particles vary in size from small ice crystals to larger hailstones, but in the rising and sinking motions within the storm there are a lot of collisions between the particles. This causes a separation of electrical charges. Positively charged ice crystals rise to the top of the thunderstorm, and negatively charged ice particles and hailstones drop to the middle and lower parts of the storm. Enormous charge differences (electrical differential) develops. "
"A moving thunderstorm gathers another pool of positively charged particles along the ground that travel with the storm. As the differences in charges continue to increase, positively charged particles rise up taller objects such as trees, houses, and telephone poles. Have you ever been under a storm and had your hair stand up? Yes, the particles also can move up you! This is one of nature's warning signs that says you are in the wrong place, and you may be a lightning target!
The negatively charged area in the storm will send out a charge toward the ground called a stepped leader. It is invisible to the human eye, and moves in steps in less than a second toward the ground. When it gets close to the ground, it is attracted by all these positively charged objects, and a channel develops. You see the electrical transfer in this channel as lightning. There may be several return strokes of electricity within the established channel that you will see as flickering lightning."
"The lightning channel heats rapidly to 50,000 degrees. The rapid expansion of heated air causes the thunder. Since light travels faster than sound in the atmosphere, the sound will be heard after the lightning. If you see lightning and hear thunder at the same time, that lightning is in your neighborhood! "
"Not all lightning forms in the negatively charged area low in the thunderstorm cloud. Some lightning originates in the cirrus anvil at the top of the thunderstorm. This area carries a large positive charge. Lightning from this area is called positive lightning. This type is particularly dangerous for several reasons. It frequently strikes away from the rain core, either ahead or behind the thunderstorm. It can strike as far as 5 or 10 miles from the storm, in areas that most people do not consider to be a lightning risk area. The other problem with positive lightning is it typically has a longer duration, so fires are more easily ignited. Positive lightning usually carries a high peak electrical current, which increases the lightning risk to an individual. "
"Each spark of lightning can reach over five miles in length, soar to temperatures of approximately 50,000 degrees Fahrenheit, and contain 100 million electrical volts. "
"At any given moment, there are 1,800 thunderstorms in progress somewhere on the earth. This amounts to 16 million storms each year! "
"Lightning has been seen in volcanic eruptions, extremely intense forest fires, surface nuclear detonations, heavy snowstorms, and in large hurricanes, however, it is most often seen in thunderstorms."
"Ice in a cloud seems to be a key element in the development of lightning. Storms that fail to produce quantities of ice may also fail to produce lightning. In a storm, the ice particles vary in size from small ice crystals to larger hailstones, but in the rising and sinking motions within the storm there are a lot of collisions between the particles. This causes a separation of electrical charges. Positively charged ice crystals rise to the top of the thunderstorm, and negatively charged ice particles and hailstones drop to the middle and lower parts of the storm. Enormous charge differences (electrical differential) develops. "
"A moving thunderstorm gathers another pool of positively charged particles along the ground that travel with the storm. As the differences in charges continue to increase, positively charged particles rise up taller objects such as trees, houses, and telephone poles. Have you ever been under a storm and had your hair stand up? Yes, the particles also can move up you! This is one of nature's warning signs that says you are in the wrong place, and you may be a lightning target!
The negatively charged area in the storm will send out a charge toward the ground called a stepped leader. It is invisible to the human eye, and moves in steps in less than a second toward the ground. When it gets close to the ground, it is attracted by all these positively charged objects, and a channel develops. You see the electrical transfer in this channel as lightning. There may be several return strokes of electricity within the established channel that you will see as flickering lightning."
"The lightning channel heats rapidly to 50,000 degrees. The rapid expansion of heated air causes the thunder. Since light travels faster than sound in the atmosphere, the sound will be heard after the lightning. If you see lightning and hear thunder at the same time, that lightning is in your neighborhood! "
"Not all lightning forms in the negatively charged area low in the thunderstorm cloud. Some lightning originates in the cirrus anvil at the top of the thunderstorm. This area carries a large positive charge. Lightning from this area is called positive lightning. This type is particularly dangerous for several reasons. It frequently strikes away from the rain core, either ahead or behind the thunderstorm. It can strike as far as 5 or 10 miles from the storm, in areas that most people do not consider to be a lightning risk area. The other problem with positive lightning is it typically has a longer duration, so fires are more easily ignited. Positive lightning usually carries a high peak electrical current, which increases the lightning risk to an individual. "
Double Rainbow
Picture courtesy of a DC viewer!!
Some powerful storms rocked the area last night with heavy rain and lots of lightning! But before they made it to the Eastern Shore, they slammed into DC. The above picture was taken from around DC after the storms passed. It's a great shot of a double rainbow. Double rainbows aren't nearly as common as a single rainbow.
Rainbows are caused by the bending of sunlight as it goes through raindrops. The light is first refracted as it enters the surface of the raindrop, then reflected off the back of the drop, and again refracted as it leaves the drop.
Rainbows appear with red on the outer part of the arch and violet on the inner section. Unfortunately, there is no pot of gold at the end of a rainbow. That's because rainbows do not actually exist at a particular location. It is an optical illusion whose position depends on the location of the sun and person viewing it. All raindrops refract and reflect the sunlight in the same way, but only the light from some raindrops reaches the observer's eye. This light is what creates the rainbow for the person. The position of a rainbow is always in the opposite direction of the Sun with respect to the observer, and the interior is always slightly brighter than the exterior.
Occasionally, a second rainbow is found. Usually these are dimmer and thicker than the primary bow. Secondary rainbows are caused by a double reflection of sunlight inside the raindrops. As a result of the second reflection, the colors of a secondary rainbow are in reverse order compared to the primary bow. Violet appears on the outside and red is visible on the inside.
Information courtesy wikipedia.com
Monday, June 23, 2008
Lightning Safety Awareness Week
June 22nd through the 28th is Lightning Safety Awareness Week.
According to NOAA, "on average, 62 people die every year from lightning strikes, with hundreds of additional injuries reported."
Here are a few safety pointers from NOAA.
Source: www.noaa.gov
According to NOAA, "on average, 62 people die every year from lightning strikes, with hundreds of additional injuries reported."
Here are a few safety pointers from NOAA.
If you are indoors:
"*Avoid contact with electrical equipment or cords. If you plan to unplug any electronic equipment, do so well before the storm arrives.
*Avoid contact with plumbing. Do not wash your hands, do not take a shower, do not wash dishes, and do not do laundry.
*Avoid contact with corded phones.
*Stay away from windows and doors, and stay off porches.
*Wait 30 minutes after you hear the last rumble of thunder before going out again."
If you are outdoors:
"*Do not seek shelter under tall or isolated trees. Lightning typically strikes the tallest object in an area.
*Avoid open areas. You don’t want to be the tallest object.
*Do not seek shelter under partially enclosed buildings.
*If you are camping, be ready to seek safe shelter in a vehicle or substantial building if a thunderstorm threatens. A tent offers no protection from lighting.
*Stay away from metal fences and poles that could conduct lightning to you.
*If you are on a boat, return to shore immediately and seek safe shelter."
*Avoid contact with plumbing. Do not wash your hands, do not take a shower, do not wash dishes, and do not do laundry.
*Avoid contact with corded phones.
*Stay away from windows and doors, and stay off porches.
*Wait 30 minutes after you hear the last rumble of thunder before going out again."
If you are outdoors:
"*Do not seek shelter under tall or isolated trees. Lightning typically strikes the tallest object in an area.
*Avoid open areas. You don’t want to be the tallest object.
*Do not seek shelter under partially enclosed buildings.
*If you are camping, be ready to seek safe shelter in a vehicle or substantial building if a thunderstorm threatens. A tent offers no protection from lighting.
*Stay away from metal fences and poles that could conduct lightning to you.
*If you are on a boat, return to shore immediately and seek safe shelter."
Source: www.noaa.gov
Sunday, June 22, 2008
On This Day
On Thursday the landfall of Hurricane Agnes was mentioned, today in history that hurricane had an impact on our area:
"1972 - The remnants of Hurricane Agnes cause tremendous rains of 10-20 inches across Maryland, Virginia, New York and Pennsylvania. Tremendous flooding occurred in Pennsylvania. Much of Wilkes-Baare, Pennsylvania was destroyed when floodwaters breached a dike and a wall of water inundated the town. $3.5 billion in damage and 122 killed as a result of the floods."
Not about our area, but since the Midwest has been seeing a lot of tornadoes and flooding, here are more facts about this day in history related to those topics.
"1919 - 59 people were killed as an F5 tornado ripped through the town of Fergus Falls, Minnesota. 400 buildings were destroyed. A blank check was found over 60 miles away and lumber was carried 10 miles."
"1947 - 12 inches of rain fell in 42 minutes at Holt Missouri to set a new world record for intense rainfall. The record would be tied in January 24-25, 1956 in Hawaii at the Kilauea Sugar Plantation."
Source: http://www.theweathercompany.com/cgi-bin/wxnotebook.pl
"1972 - The remnants of Hurricane Agnes cause tremendous rains of 10-20 inches across Maryland, Virginia, New York and Pennsylvania. Tremendous flooding occurred in Pennsylvania. Much of Wilkes-Baare, Pennsylvania was destroyed when floodwaters breached a dike and a wall of water inundated the town. $3.5 billion in damage and 122 killed as a result of the floods."
Not about our area, but since the Midwest has been seeing a lot of tornadoes and flooding, here are more facts about this day in history related to those topics.
"1919 - 59 people were killed as an F5 tornado ripped through the town of Fergus Falls, Minnesota. 400 buildings were destroyed. A blank check was found over 60 miles away and lumber was carried 10 miles."
"1947 - 12 inches of rain fell in 42 minutes at Holt Missouri to set a new world record for intense rainfall. The record would be tied in January 24-25, 1956 in Hawaii at the Kilauea Sugar Plantation."
Source: http://www.theweathercompany.com/cgi-bin/wxnotebook.pl
Saturday, June 21, 2008
The Other Side
As a meteorologist/journalist, it is always important to look at both sides of every issue, including "Global Warming."
This blog simply presents another side to the previous blog, "Eye Into the Future."
This blog is not implying that our weather team believes Global Warming is/is not occuring, it is simplying posting direct quotes from an article found discussed on a weather forum.
All quotes and diagrams are taken directly from The Register: "Is the earth getting warmer, or cooler? A tale of two thermometers" by Steven Goddard. The article goes further into detail and can be found at this link: http://www.theregister.co.uk/2008/05/02/a_tale_of_two_thermometers/
"Two authorities provide us with analysis of long-term surface temperature trends. Both agree on the global temperature trend until 1998, at which time a sharp divergence occurred. The UK Meteorological Office's Hadley Center for Climate Studies Had-Crut data shows worldwide temperatures declining since 1998. According to Hadley's data, the earth is not much warmer now than it was than it was in 1878 or 1941. By contrast, NASA data shows worldwide temperatures increasing at a record pace - and nearly a full degree warmer than 1880."
Hadley's Data from April 2008
NASA's Data from April 2008
"The other two widely used global temperature data sources are from earth-orbiting satellites UAH (University of Alabama at Huntsville) and RSS (Remote Sensing Systems.)"
"Confusing? How can scientists who report measurements of the earth's temperature within one one-hundredth of a degree be unable to concur if the temperature is going up or down over a ten year period? Something appears to be inconsistent with the NASA data - but what is it?
One clue we can see is that NASA has been reworking recent temperatures upwards and older temperatures downwards - which creates a greater slope and the appearance of warming. Canadian statistician Steve McIntyre has been tracking the changes closely on his Climate Audit site, and reports that NASA is Rewriting History, Time and Time Again. The recent changes can be seen by comparing the NASA 1999 and 2007 US temperature graphs."
This blog simply presents another side to the previous blog, "Eye Into the Future."
This blog is not implying that our weather team believes Global Warming is/is not occuring, it is simplying posting direct quotes from an article found discussed on a weather forum.
All quotes and diagrams are taken directly from The Register: "Is the earth getting warmer, or cooler? A tale of two thermometers" by Steven Goddard. The article goes further into detail and can be found at this link: http://www.theregister.co.uk/2008/05/02/a_tale_of_two_thermometers/
"Two authorities provide us with analysis of long-term surface temperature trends. Both agree on the global temperature trend until 1998, at which time a sharp divergence occurred. The UK Meteorological Office's Hadley Center for Climate Studies Had-Crut data shows worldwide temperatures declining since 1998. According to Hadley's data, the earth is not much warmer now than it was than it was in 1878 or 1941. By contrast, NASA data shows worldwide temperatures increasing at a record pace - and nearly a full degree warmer than 1880."
Hadley's Data from April 2008
NASA's Data from April 2008
"The other two widely used global temperature data sources are from earth-orbiting satellites UAH (University of Alabama at Huntsville) and RSS (Remote Sensing Systems.)"
"Confusing? How can scientists who report measurements of the earth's temperature within one one-hundredth of a degree be unable to concur if the temperature is going up or down over a ten year period? Something appears to be inconsistent with the NASA data - but what is it?
One clue we can see is that NASA has been reworking recent temperatures upwards and older temperatures downwards - which creates a greater slope and the appearance of warming. Canadian statistician Steve McIntyre has been tracking the changes closely on his Climate Audit site, and reports that NASA is Rewriting History, Time and Time Again. The recent changes can be seen by comparing the NASA 1999 and 2007 US temperature graphs."
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