Wednesday, March 19, 2014

Tornado Watches, Warnings, and Emergencies

Before I proceed to cover the subject of tornado safety in the home in detail, I need to cover the types of severe weather statements issued by the National Weather issues and the reasons behind them.  Even today, many people tend to become confused by these statements, a fact which sometimes leads them to disregard these statements altogether.  As a result, it is little wonder that, especially in recent years, the National Weather Service has taken a close look at the wording of their severe weather statements, and is working hard to both clarify them and to better convey how the public should respond to each of them when severe weather does strike.  Since tornadoes are my primary focus at this point in this blog, I will concentrate on tornado-related statements this time around, with links to other sources of information on related topics.

Whenever it is determined that severe weather is in the making, the National Weather Service will issue one of several different types as conditions warrant:  WATCHES (to give you time to prepare), WARNINGS (to tell you it is time to act), PDS, or "Particularly Dangerous Situations," (when the potential for severe weather is unusually high, or when an outbreak is expected to be unusually intense), and, finally, "Emergency" (meaning an extreme, life-threatening situation that requires IMMEDIATE action or response).

The first of these is the Severe Weather WATCH.  This type of severe weather statement is usually the first such statement, in sequence, to be issued.  It indicates that conditions either already are, or are expected to become, favorable for the development of severe weather.  All Severe Weather Watches are issued by the Storm Prediction Center in Norman, Oklahoma, usually several hours or even as much as a day or more in advance.  Because of the scale of the weather systems involved, a Severe Weather Watch will usually cover thousands of square miles, and generally will cover a time span of from five to eight hours.

If a severe weather event is expected to be unusually strong or dangerous, the notation, "Particularly Dangerous Situation" will be added to the original message text.  This also means that a larger amount of territory will be included than a "regular" Severe Weather Watch, and will run for a longer period of time as well.

When a severe weather event is determined to either be imminent or has actually been detected, a Severe Weather WARNING will be issued.  Because such events are almost always local in nature,  a Severe Weather Warning is almost always issued by a local office of the National Weather Service, and will cover a much smaller area than a Severe Weather Watch, and will last for a much shorter period of time.  Again, the terms "Particularly Dangerous Situation" or "Emergency" (in the case of  a tornado) may be added to the original text to indicate greater than normal or even extreme levels of severity or danger.  In particular, the term, "Tornado EMERGENCY" means that an extremely dangerous, life-threatening tornado has either been spotted by trained storm spotters, detected on weather radar, or both, and that you should take IMMEDIATE action to protect yourself!

For more information on this subject, I invite the reader to consult Wikipedia, under the term, "Severe Weather Terminology."

Tuesday, February 11, 2014

Severe Weather Safety--Part 2

In choosing a NOAA Weather Radio, there are three specific features you should always look for, no matter which make or model you may have in mind.  This is important because not all receivers that bill themselves as "weather radios" have them (as I learned from personal experience!),

The first of these is battery backup.  It is not uncommon for the regular electric power to go offline for hours or even days in the wake of a severe weather outbreak.  Some weather radios may have a hand-cranked dynamo built in which can keep the radio on and running for up to an hour after using the crank for as little as 30 seconds (60 is the more usual length of time).  Even so, having batteries in the unit, and keeping some extra batteries on hand, is a wise precaution.  Be sure to rotate whatever batteries you have at least every six months to insure maximum power output and the longest possible battery life.

Next is a feature known as ToneAlert.  Whenever the National Weather Service issues a special statement of any kind, and especially if a severe weather watch or warning is issued, they will transmit a specially coded signal which will automatically cause the radio speaker to give off a loud, piercing alarm signal, usually of an "up-and-down" nature.  The code will also cause the radio to turn itself on and remain on until the user turns the set off manually.  This helps to insure that the user has enough time to hear the message and respond to it in an appropriate manner.

Last, but by no means least, is a feature known as "SAME," which stands for "Specific Area Message Encoding."  Whenever  a local Weather Service office broadcasts a ToneAlert signal, it also transmits a series of special codes to designate the geographic area or areas that the message is intended for.  On weather radios equipped with this feature, the receiver will play ONLY the messages encoded for the area they are set for, and will reject all others.  This helps to avoid confusion due to conflicting messages, thus giving the listener a clearer idea of what hazards they may be facing, and what action or actions they need to take in a given situation.

Whatever make or model of NOAA Weather Radio you choose, the instructions included with the radio should explain how to set the receiver for the proper codes for your area.  Some radios may do this automatically (handheld models, for instance), while others may require the setting a a few dials.  In any case, the radio's manufacturer should have a customer service telephone number or a website to assist the purchaser if he or she needs help.

For outdoor activities especially, having a handheld portable NOAA Weather Radio receiver is one of the most important safety measures you can take, especially where children are involved.  In any such activity, someone should be designated to monitor the radio, and sound a warning if an alert of any sort is issued.

The next posting in this series will go into the basics of severe weather safety in the home.

Wednesday, January 29, 2014

Severe Weather Safety--Part 1

As any weather forecaster with any experience will tell you, severe weather, especially tornadoes, can occur anywhere on Earth, any day of the year, and at any time of the day or night--IF the right conditions exist.  Because of this fact, perhaps the single most important step you can take to protect yourself and those you love from the threat of severe weather is simply to keep abreast of changing weather conditions.  This is especially important during the two primary "tornado seasons" that occur each year.  As I mentioned in an earlier posting, the first and primary season is from March through June, while the second is generally from October through early December, especially in the region known as "Dixie Alley."

By far, the single most important means of keeping abreast of changing weather conditions is the NOAA Weather Radio network.  Since the early 1950's, and especially since the mid-1970's the National Weather Service has worked to establish a nationwide network of radio stations devoted to making the latest weather information available to the public.  There are now more that 450 of these transmitters in active operation, broadcasting on frequencies between 162.4 and 162.55 Megahertz on the Public Service Radio Band, which is established and allocated by the Federal Communications Commission.  Through partnerships with other government agencies and local industries, efforts are now under way to expand the network still further, with a goal of reaching not less than 95% of the American public, broadcasting not only weather information, but also information on marine weather hazards, earthquake and volcanic activity, hazardous material emergencies, and even Amber Alerts.

While most commercial radio and television broadcasters do an excellent job of keeping the public informed in such instances, they would be the first to agree that having a NOAA Weather Radio receiver in your home is still an important defense against the threat of severe weather of any kind.  These receivers are available at prices ranging from around $20 to $50, and can be purchased at many local electronics stores, department stores, and, in a growing number of areas, in many larger grocery stores, to say nothing of online vendors.

In my next posting, I'll go into what features you should look for when choosing a specific weather radio, and the reasons behind them.

Sunday, January 19, 2014

Why So Many Tornadoes In The US?

In order to understand why so many tornadoes occur in the United States, take a look at a topographical map of the North American continent, and especially of the United States.  The Rocky Mountain range in the west, and the Appalachian Mountain range in the east, act like the sides of a gigantic natural funnel, allowing huge amounts of warm, moist air from the Gulf of Mexico, cold, dry air from Canada and the Arctic, and cool, dry air spilling over the Rockies from the Pacific (losing most of its moisture in the process) to come into contact--and often, conflict!  When these three thermally unbalanced air masses meet, the reaction is almost always violent, and, in many cases, downright catastrophic!

The primary field of conflict, so to speak, is an area generally known as "Tornado Alley."  It stretches from Texas all the way up to Minnesota. Better than 95% of the more than 1,000 tornadoes that occur in the United States each year (on average) occur in this region.  Because of this, most of the research into severe weather and severe weather safety are concentrated in this area.  In fact, the National Weather Service maintains two major facilities for this purpose in Norman, Oklahoma, often referred referred to as "the heart of Tornado Alley."  The first of these, the National Severe Storms Laboratory, is devoted primarily to severe weather research, while its counterpart, the Storm Prediction Center, is dedicated to actively predicted to forecasting severe weather, and alerting the public when it actually develops.

 In recent years, a second area, commonly referred to as "Dixie Alley," has been identified.  It includes the states of Mississippi, Louisiana, Alabama, the upper half of Georgia, and the western 2/3 of Tennessee.  A number of the most destructive tornadoes in recent years have occurred, many of them at night, and more than a few of them in what would normally be considered the "dead of winter."  The reason for this is that the "Dixie Alley" region is significantly closer to the Gulf of Mexico than the traditional "Tornado Alley."  This creates a sort of "thermal flywheel" or "thermal storage battery" effect, allowing severe weather to develop much later in the day, and in the year, than might otherwise be expected.

In most areas of the United States, there are two periods when tornadoes, and the severe thunder-storms that spawn them, are most likely to develop.  Both of these periods are times of transition from one season to the next.  The primary season includes the months of March, April, and May, which is the transitional period between winter and summer.  The secondary period includes late October, November, and early December, the seasonal transition between summer and winter.  This especially holds true in the region known as "Dixie Alley."  Also, and especially in "Dixie Alley," most tornadoes tend to develop late in the day, when the heat and humidity reach their daily peak.  This is also the reason so many tornadoes occur at dusk, or even in the early nighttime hours.  It should also be noted that tornadoes which occur at night are all but impossible to see, which makes them even more dangerous than their daytime counterparts.

In my next posting, we'll begin covering the basic safety measures to protect you, and those you love, against the dangers of severe weather, and especially tornadoes.

Monday, January 6, 2014

Just What IS A Tornado?

In order to properly understand and practice the principles of severe weather safety, we must first understand the major players involved, so to speak.  When most people hear the the words "severe weather" or "severe weather safety," they almost always think of tornadoes, and for good reason.  Such being the case, let's begin delving into the subject of sever weather safety by defining what is, and is not, a tornado.

The word "tornado" is of Spanish origin, and, literally translated, means "twisting" or "turning"--an apt description of the appearance of this most frightening severe weather phenomenon.  The National Weather Service defines a tornado as, "a violently rotating column of air attached to a thunderstorm AND in contact with the ground."  If the column of air is not in contact with the ground, it is referred to as a "funnel cloud."  Some people might well consider this to be an unnecessarily picayunish distinction.  However, it has proven to be an essential one to permit the keeping of clear, consistent, accurate records, which are the basis of all severe weather research.

No matter what you think about this distinction, however, the fact remains that the North American continent in general, and the United States in particular, experience more, and more violent tornadoes than all the rest of the world put together!  In the year just ended, some 940 tornadoes were confirmed by the National Weather Service, causing a total of 54 deaths, and more than $2.6 billion in property damage.

In my next posting, we'll go into the reasons why so many of these horrific storms take place here in America, and the beginnings of what you can do to help protect yourself and those you love from their destructive fury.

Friday, January 3, 2014

Relative humidity and home heating comfort

This afternoon, I've had several phone calls from people who were concerned about my staying warm during this cold snap.  That caused me to become concerned about a major factor in home heating comfort that I am afraid many of you may be neglecting.  That factor is the relative humidity level (that is, the amount of moisture in the air relative to the temperature) in one's home or apartment.

Why is this so important, you ask?  Well, from my own experience, I can testify that, with the right level of relative humidity in the air (approximately 50%), you can cut back your thermostat by as much as ten degrees or more and still feel warm and toasty.  This amounts to a significant savings on your next gas or electric bill!  It also makes you less susceptible to colds, flu, and other diseases, since dry air puts a strain on the delicate tissues of the mouth, nose, and throat.

Having said all of that, however, it is just as important not to let the humidity level get too high, as that will tend to promote the growth of mold and mildew, especially black mold, which can be deadly.  It is easy, however, to monitor the humidity level in your home with an inexpensive humidity gauge, available at many hardware stores or home furnishing stores.  Moisture can be added to the air very easily when needed by means of an old-fashioned steam vaporizer or cool-mist vaporizer which are currently priced at from $15 to $30 at most drug and department stores.  They're easy to care for, so this is basically a one-time purchase.

Please feel free to spread the word about this important subject.  With the home heating season now in full swing, the home humidity level is an important factor for both health and economy reasons--please don't neglect it!

The Importance Of Severe Weather Safety

The year 2013 was an unusual one in terms of severe weather in several different ways.  While there were only 940 tornadoes recorded by the National Weather Service (as opposed to an average of up to 1300), the violence of several of these monster storms more than made up for the seeming deficiency in numbers.  Furthermore, the amount of property damage inflicted by these storms made them among the costliest natural disasters in U.S. history.  All in all, a total of $2.6 billion worth of houses and other structures were either severely damaged or destroyed outright.

Two of these storms in particular stand out in the minds of the "severe weather community."  The first of these took place in Moore, Oklahoma, not far from Oklahoma City, on May 20, 2013.  For the third time since 1999, this area was pounded by an EF5 tornado, with winds estimated as high as 210 mph.  Two elementary schools were torn apart by the 1.3 mile-wide behemoth.  In the case of the second school, Plaza Towers Elementary, 7 children lost their lives to the storm's fury.  In all, 24 people were killed, 1150 homes were destroyed, and the total property damage reached an incredible $2 billion, making it the single costliest natural disaster of the year.  Incredibly, many meteorologists estimated that this storm released as much as 600 times more energy that the 20 kiloton atomic bomb dropped on Hiroshima, Japan, in August of 1945!

Just 11 days later, on May 31, 2013, another twister struck the area of El Reno, Oklahoma, some 25 miles southwest of Oklahoma City.  Although this storm was finally rated an EF3 in terms of ground damage, several radar readings indicated winds speeds as high as 296 mph, the second highest wind speeds ever recorded.  Furthermore, the funnel generated by this storm reached a stunning 2.6 miles in width, wider even the tornado that struck Hallam, Nebraska, in 2004.

Thankfully, because this storm's path was primarily over open terrain, property damage was a mere $35-$40 million, as compared to the $2 billion in damage caused by the May 20th storm.  Sadly, however, 8 people died as a result of this twister's fury.  Of these, 3 were well-known professional storm chasers, who were caught off guard by a sudden change in the storm's direction.  Furthermore, Weather Channel meteorologist Mike Bettes and his crew were also caught off guard, and their car was tossed more than 200 yards by the violent winds.  Thankfully, Bettes and one of his crew suffered only minor injuries, while the third member suffered multiple fractures and had to be hospitalized.  (It was later revealed that the three professional storm chasers, in a possible error in judgment, had used a non-reinforced subcompact car, rather than the heavily reinforced 3/4 ton truck that was their normal vehicle of choice for storm chases.)

By far the most disturbing aspect of this particular incident, however, was the fact that many thousands of people attempted to evacuate the area, in spite of the fact that most severe weather experts strongly advise against anything of the sort during a tornado.  To make matters worse, the roads around Oklahoma City were already clogged with afternoon rush hour traffic.  The result, as described by numerous local residents, was utter chaos and confusion.  (Part of the reason for the evacuation may very well have been an extremely ill-advised and controversial recommendation by a local TV weatherman that those who did not have access to safe rooms or underground storm shelters should attempt to outrun the storm in their cars, again contrary to the recommendation of the vast majority of severe weather experts.  In this writer's opinion, that weatherman should have been severely reprimanded, at the very least, on the grounds of inciting a panic!)

This incident, perhaps more than any other in recent memory, underscores the importance of making clear, accurate information on the subject of severe weather safety available to everyone, and of reminding the public of their own responsibility to act on such information once they get it!  To that end, I will be posting articles on various topics relating to severe weather safety throughout 2014.  Links to relevant sites will be posted as well, and, if there is sufficient interest, questions from visitors will be answered online.

The bottom line on the subject of severe weather safety is that, while these storms can be undeniably frightening, and the sheer power they contain should definitely be respected, there is so reason for panic if you know what to look for, what to expect, and most of all, what to do when severe weather does strike.  That is precisely what my efforts on this blog this coming year will be all about.