Safest Places to Live to Avoid Severe Weather

We all love the good old U.S.A., but one of the downsides of living here is that it's one of the most dangerous countries for severe weather in the world!  No location in the U.S. is completely safe from weather extremes, but there are some locations that are safer than others.

First let's keep in mind all the types of severe weather threats there are. There's ice/snow storms, thunderstorms, tornadoes, floods, tropical cyclones, extreme cold, and extreme heat. When you consider all these threats, it's hard to find a place you can consider truly weather safe, but let's give it a shot.

As a general rule, the farther north you go in the U.S., the safer you'll become.  Yes the threat from extreme cold and ice/snow storms increases, but the colder weather also significantly decreases the threats of excessive heat, thunderstorms, and tornadoes which are far bigger killers than cold weather events.  To avoid the threat of flooding, you want to be far away from a river to avoid traditional flooding and in an area with deep topsoil to avoid flash floods.  To avoid tropical storms and hurricanes, you want to stay away from the coasts.

Considering all the factors above, one particularly safe location is Northern Minnesota.  Thunderstorms are not particularly common, so very few worries about lightning and tornadoes.  It's FAR away from any coastlines so it's essentially immune to tropical cyclones. Heavy rain isn't common and there are no major rivers you have to worry about flooding.  While the threat from extreme cold doesn't get much worse than Northern Minnesota, cold causes the fewest weather related deaths each year.  Snow and ice storms can be a threat as well, but not as great as other locations slightly farther south which typically see greater snowfall. 

So the weather in Northern Minnesota is not likely to kill you, but let's face it, that cold sure is a bummer!  So is there a place with better weather that's even safer?  Yes there is.  May I present, Southern California, the safest place from severe weather in the country!

There's a reason so many people live here...the weather is terrific!  Extreme cold and snow storms?  Forget about it!  While this area would normally be concerned about excessive heat, the Pacific Ocean keeps temperatures moderate even in the summer months.  Rain falls more from showers than thunderstorms which reduces multiple weather threats.  No heavy rain or rivers to worry about flooding.  While this area is on the coast, the cold waters of the Pacific severely limit tropical cyclone activity, making Southern California an exception to the coast rule. 

Yes, Southern California would be far and away the safest place from natural hazards in the country if it weren't for the non-weather threats...wildfires and earthquakes!  Unfortunately, these risks are so great that they start to outweigh all the benefits from the safe weather.  So maybe it's back to Northern Minnesota after all... :(

Where is the Best Place to Take Shelter During a Tornado?

With tornado season heating up, it's important to know where you should and shouldn't take shelter if you find yourself under a tornado warning.

The safest place to be is certainly a basement or separate storm shelter.  While tornadoes can do extreme damage at the surface, they do not have the power to harm things underground.  While some people have died while taking shelter in basements due to debris from above falling in, the survival rate in a basement or storm shelter is by far the highest of any other location.

Unfortunately, basements are rare in many portions of the country.  If you or a neighbor does not have a basement, the next best location to seek shelter is the first story of any permanent building or home.  Roofs are a weak point on buildings, so it's important to put as much distance between you and the roof during a tornado.  Head to the most interior room that doesn't have any windows.  Walk-in closets are a good option and bathrooms are probably the best.  There have been many examples of people riding out tornadoes in their bathtubs.  If you have time, placing blankets or clothes on top of you can give you added protection from flying debris.  Most importantly, protect your head.  Use your hands at least, but a bike helmet is even better.  Yes it looks ridiculous, but you won't feel dumb if it saves your life!

It's important to mention that trailers/mobile homes are NOT a safe location to take shelter during a tornado.  Even weak tornadoes can do significant damage to these structures.  If you're in a mobile home and a tornado warning is issued, get out and head to the nearest permanent building.  Vehicles are also not a safe place to take shelter and should only be used if you have to travel to a permanent building.  Just look at what a tornado did to some parked tractor trailers near Dallas!

Follow these rules and you'll be well on your way to staying safe should you find yourself in the path of a tornado.

How Do Hurricanes Get Their Names?

This week brought news that the name Sandy was being retired as a potential name to be given to future hurricanes.  But what does it mean to "retire" a name?  Well it all starts with the chart below:



This shows the list of potential names that could be used to name tropical cyclones in the Atlantic Ocean for the upcoming years.  These are the only lists of names that are used, each one being used every six years.  For example, the list of names from 2012 will again be used in 2018. 

All the names were chosen by the World Meteorological Organization's hurricane committee.  Each list has an equal number of both male and female names.  You may notice some names you've rarely heard in the United States.  That's because the committee set out to include names that are common not only to English speakers, but Spanish and French speakers as well. 

Once a tropical cyclone reaches tropical storm status (winds of at least 39 mph) it is assigned a name.  The first tropical storm of the season will be assigned the "A" name, the next the "B" name, and so forth.  The names alternate between male and female, so you'll never have two storms of the same gender back to back.  If there are so many storms in one year that all the names on the list are used up, names from the Greek alphabet (Alpha, Beta, Gamma, etc) are used until the end of that year. 

As we all know, some storms end up causing much more devastation than others.  These are the ones that leave deep emotional scars and are still talked about years later.  To avoid insensitivity and confusion, each year the same committee that picked the names meets to decide if any storms from the previous year were significant enough that their name should be retired and replaced with another.  The committee has done this 77 times just in the Atlantic, including names like Andrew, Rita, Camille, and Katrina.  Sandy was the only name retired this year and it will be replaced by Sara beginning in 2018.

How Does Your Car Protect You From Lightning?

While taking shelter in a permanent structure is always the best course of action during a thunderstorm, vehicles are generally regarded as a safe alternative.  Only tornadic winds have the strength to flip a typical vehicle and while cars may be dented, only exceptionally large hail will actually break through the windows.  Most importantly, vehicles are known to be a safe place to avoid being struck by lightning.  But how do vehicles protect us from lightning and do all vehicles protect us equally?

A common belief is that the rubber tires on cars insulate the vehicle from the ground, protecting the occupants should lightning strike.  While rubber is an electric insulator, the amount of voltage carried by a lightning bolt is far too great to be insulated by rubber.  It is not the tires of vehicles, but their metal frames which protect you from lightning.  When lightning strikes a vehicle, the metal frame of the car absorbs the electricity, conducts it around the occupants, and into the ground.  This means that as long as you're not touching anything metal inside your car at the moment of the strike, you will not be harmed.

Since it's the metal frame that protects you, it's important to note that only vehicles with a hard top are a safe refuge during a thunderstorm.  Even though convertibles have metal in them too, metal only conducts electricity; it does not attract it.  If you're inside a convertible, a lightning strike could miss the metal frame, easily burn through the soft top, and strike you inside.

Check out the BBC video below to see what happens when a lightning simulator is used on a car with a person inside.  The results are quite impressive!

         

Decoding Dew Point and Relative Humidity

Dew point and relative humidity are terms that show up frequently during TV weathercasts and on weather apps, but they can be confusing and misunderstood.  These are the two main ways we describe the amount of moisture that's present in the atmosphere.  They tell us how humid it is outside and help meteorologists determine if it will rain or not.  Is one measure better than the other?  Let's look at both a little closer to find out.

Relative Humidity

Relative humidity is a measure of the amount of water vapor in the air compared to the maximum amount of water vapor the air can hold at that temperature.  It is always expressed as a percent.  For example, say it's 60 degrees outside and the relative humidity is 50%.  That means that the air is holding half the moisture it potentially could.  If it's 60 degrees outside and the relative humidity is instead 100%, that means that the air is now holding the maximum amount of moisture it can, meaning the air is saturated.

The warmer the air, the more moisture it can hold.  This means that the temperature of the air is critical in calculating relative humidity.  The graphic below is very helpful in understanding this.  The blue ball represents the actual water vapor present in the air and the yellow ball represents the maximum amount of water vapor air at that temperature could hold.  Even if the amount of water vapor in the air doesn't change, the relative humidity will change if the air temperature changes. 

The relative humidity can change dramatically in just one day, with lower values appearing in the afternoon when temperatures are higher, and higher values appearing at night when air temperatures are lower.  This is why you have to be careful when looking at relative humidity values.  Relative humidity is helpful for seeing how close air is to being saturated, but it really isn't a good measure of how humid it feels outside.  If there isn't much moisture in the atmosphere but the temperature is low enough, you can get a high relative humidity, but it really won't feel humid outside.  Because of this, meteorologists prefer to look at dew point temperatures to measure how much water vapor is in the air.

Dew Point

The dew point is the temperature at which air will become saturated.  Below this temperature, condensation will begin to occur and dew will form on the surface of objects.  Think about a can of soda you just took out of the refrigerator.  The can is dry when you're inside, but as soon as you go outside on a humid day, little drops of water (dew) form on the outside of the can.  The can is so cold that it has caused the water vapor in the air right around it to condense into liquid form.  This means the temperature of the can is at or below the dew point temperature of the air. 

The dew point temperature is dependent on the amount of water vapor in the air and will usually be lower than the current air temperature and will never be higher than it.  When the dew point and air temperature are the same, the air will be saturated and the relative humidity will be 100%.

How humid will it feel at certain dew points?  A dew point below 45 is considered low and represents dry air.  Dew points between 45 and 65 represent moderate amounts of moisture and feel comfortable.  Once the dew point climbs above 65 degrees, you will likely start to notice that it feels muggy and humid outside.  Should the dew point climb into the 70s, you'll likely start hearing the bad hair day talk start up!  If you keep these values in mind, you should have a much better grasp of how humid it is outside when you see a dew point temperature listed. 

So while relative humidity is a good measure of how close we are getting to the dew point, it's the actual dew point temperatures that really tell us the moisture content of the air.  Even though we all like percentages, try to use dew point instead of relative humidity to determine how humid it is outside.  Trust me, you'll make any meteorologist a little happier if you ask them what the dew point is instead of the relative humidity :)

What is a Severe Thunderstorm?

Severe thunderstorms are the most dangerous kind of thunderstorms.  You hear about them in the news, but what exactly makes a severe thunderstorm different from a regular thunderstorm?

Many believe that the amount of lightning in a thunderstorm is how storms are classified as severe or not.  While lightning is a significant threat, all thunderstorms contain lightning and some weaker thunderstorms can still contain a high amount.  Rainfall rate is also not a factor in classifying a storm as severe or not, though severe thunderstorms typically do have higher rainfall rates. 

There are three things that can cause a thunderstorm to be classified as severe.  If a severe thunderstorm warning is issued, the National Weather Service is doing so because they have been notified or suspect that one or more of the following is present:

1. Hail One Inch in Diameter or More

Not so long ago, the requirement for a severe thunderstorm was hail that was only 3/4" in diameter.  More research proved that while hail this size or smaller can destroy some crops, it really doesn't damage buildings or vehicles.  Once hail reaches an inch in diameter though (about the size of a quarter) it can begin to dent cars and damage roofs.  Hail that size falls from the sky at about 50mph, so it can certainly hurt you as well!

2. Wind Gusts of 58 mph or More

This may seem like a random number, but there is something to it.  Studies have shown that this is about the wind speed that branches begin to break off from tree trunks.  It is also important to note that the winds don't have to be sustained at 58 mph or greater; they just have to be gusting up to that speed.  It's very unlikely to have winds constantly at this speed in a thunderstorm unless...

3. Tornado

Any thunderstorm that produces or is suspected of producing a tornado is automatically classified as severe.  When this occurs however, you won't see a severe thunderstorm warning issued, but a tornado warning.  This means that if you are under a tornado warning, you are also experiencing a severe thunderstorm.

Any of the above three conditions can be very dangerous, so do not take severe thunderstorm warnings lightly!

Got anymore questions about severe weather?  Let me know in the comments below!

Top Five Tornado Myths

With winter winding down, temperatures are warming up and the likelihood for severe weather and tornadoes is also increasing.  We've already had an EF-4 tornado go through a heavily populated area (Hattiesburg) this month, so I'm taking the time now to debunk some myths about tornadoes and tornado safety.  The number of myths is surprisingly large, but we can't get too lengthy and since I like countdowns, I'm going to focus on the five myths that stand out to me as being the most flagrantly wrong.

5. You Can Rate a Tornado Just by Looking at it.

I blame the movie Twister for this one.  Throughout the movie, they constantly look at tornadoes and say, "That's a F-3," or "There's a F-5 heading our way!"  This is all wrong.  The width of a tornado gives a general idea of the intensity, but there are plenty of examples of relatively skinny tornadoes that had higher winds than other wider ones.  It is nearly impossible to measure the wind speed of a tornado as they are happening as the instruments would likely be destroyed.  The F or Fujita Scale was developed as a way to estimate the wind speed of tornadoes based on the damage they left behind.  To evaluate the damage, the tornado has to already have passed, which is why the official Fujita Scale rating of a tornado is usually not announced by the National Weather Service until a day after the storm.  So you might not know how strong a tornado is before it hits, but it doesn't matter.  Every tornado is dangerous and requires your immediate action.  Also, to be correct, it's not the F Scale anymore but the EF or Enhanced Fujita Scale.  The original scale was tweaked back in 2007 to make it more accurate.  The image below shows you how the scale breaks down:

4. It's Better to Stay Inside a Mobile Home Than Leave.

While it is almost always better to be indoors than outdoors during a tornado, there is an exception when it comes to mobile homes/trailers/manufactured homes.  Mobile homes are much more likely to be destroyed by a tornado than a permanent building.  Most mobile homes are only designed to sustain winds up to 70 mph; the strength of an EF-0 tornado.  Mobile homes also frequently flip over in tornadoes, because it is so easy for winds to get underneath the home and lift it.  If you are in a mobile home and a tornado warning is issued, get out!  If a permanent building is nearby, go there and seek shelter on the lowest floor.  If there is not one close by, you're still better off getting in your vehicle and driving to another location or seeking shelter in a low lying place outside the mobile home than remaining inside.

3. A Highway Overpass is a Safe Place to be.

It's no mystery that a car is not the safest place to be in a tornado.  They can be flipped over relatively easily and outrunning a tornado only works under ideal circumstances.  The idea that stopping your car under a highway overpass and taking shelter underneath it is a better option though is a misconception.  There are documented cases of people surviving a tornado under an overpass, but there are more cases of people not surviving.  Overpasses often act like a wind tunnel, enhancing the speed of the wind and providing a location for debris to gather.  If you find yourself in a car during a tornado warning, do not stop under an overpass, but continue driving to the closest permanent building.  If you see the tornado and have no direction to escape in, then you're still better off getting out of your vehicle and taking shelter in a ditch or other low lying area than taking shelter under an overpass.

2. Tornadoes Do Not Cross Rivers or Hills.

Some believe that if they can get to the opposite side of a river from a tornado they will automatically be safe.  This is just not true, as tornadoes have been documented crossing rivers and continuing on the other side.  A tornado is just as likely to occur over water as land; over water they're known as waterspouts instead of tornadoes.  The image below is of a waterspout that formed at sea.  Another common belief is that tornadoes only occur in flat areas and cannot cross over hills.  This too has been proven false.  While most tornadoes do form over flat terrain, they have also occurred in the mountains and have tracked for miles over hilly terrain.

1. Opening the Windows in a House Before a Tornado Hits Will Help Protect it.

This may be the biggest tornado safety myth that's still widely believed.  The idea is that opening all the windows in a house will help equalize the pressure between the inside and outside of the house and keep it from being crushed.  While tornadoes are associated with lower atmospheric pressure, research has shown that it is the winds and debris being carried by the tornado that destroy homes, not the pressure change.  Taking the time to open all the widows in your home only wastes valuable minutes when you could be taking shelter in the safest part of your home.  A strong tornado will break the windows anyway and should the tornado not pass over you, you will avoid having rain and debris blown into your house.

So there you have my top five tornado myths.  If you want more information on tornadoes and tornado safety this is a great website to check out: http://www.ready.gov/tornadoes

And as always if you have any other weather questions, be sure to comment below!

Partly Cloudy vs. Partly Sunny

There are lots of terms in meteorology that are very similar and that's part of what leads to the confusion that exists out there.  The two terms in the title of this week's blog post are a great example.  Partly cloudy and partly sunny are two terms that pop up in weather forecasts a lot, but what's the real difference between the two?

To try and answer this, let's start by looking up the definition given by the federal organization that sets the standards for the field of meteorology in the United States: the National Oceanic and Atmospheric Administration (NOAA).  In the Federal Meteorological Handbook, NOAA describes five categories of cloud cover that should be documented at all weather observing stations.  The list includes the following:

Clear = No visible clouds
Few = 1/8 - 2/8 of sky covered by clouds
Scattered = 3/8 - 4/8 of sky covered by clouds           
Broken = 5/8 -7/8 of sky covered by clouds
Overcast = 100% cloud cover

Though these five terms are all the description NOAA deems necessary to describe sky cover, there's a lot of room for interpretation.  A big problem is that unless you're in the meteorology field, most people don't look at the sky in eighths and the difference between scattered and broken could be large.  To try and relate to the public better and keep forecasts more interesting, forecasters at the National Weather Service (which is a part of NOAA) decided to come up with their own categories for sky cover.  Here's the list they use:

 

Cloudy = 90-100% sky cover
Mostly Cloudy = 70-80% sky cover
Partly Cloudy/Partly Sunny = 30-60% sky cover
Mostly Clear/Mostly Sunny = 10-30% sky cover
Clear/Sunny = 0-10% sky cover
Fair = Less than 40% cloud cover, no
precipitation and no extreme weather

They too only have five categories (not counting fair), but they added different terms to describe the same conditions.  As far as the NWS is concerned, partly cloudy and partly sunny are the same thing.  The only difference is that partly sunny is used to describe daytime cloud cover and partly cloudy is used to describe nighttime cloud cover.  Same goes with mostly sunny/mostly clear and clear/sunny.

So case closed right?  Not so fast.  Because the terms are so similar, the nighttime and daytime terms often get used interchangeably by most forecasters.  If skies are expected to be partly sunny for the next five days, it's highly likely the forecaster will switch between saying partly sunny, partly cloudy, and fair just to spice up the forecast some.

The difference between partly cloudy and partly sunny though has really taken on a life of its own; so much so that many forecasters now separate the two terms to have a total of six categories of sky cover instead of five.  The most common order of these six categories of sky cover, from least to greatest, is as follows:

Sunny = 0-10%
Mostly Sunny = 10-30%
Partly Cloudy = 30-50%
Partly Sunny = 50-70%
Mostly Cloudy = 70-90%
Cloudy = 90-100%

This is the scale I personally go by, but even this is not agreed upon by all meteorologists.  Some argue that partly sunny and mostly cloudy mean the same thing while others use partly sunny when cloud cover is expected to dissipate later and partly cloudy when cloud cover is expected to increase later. 

The bottom line is that it depends on the person who made the forecast for what partly cloudy or partly sunny actually means.  While you're more likely to see more clouds when the forecast calls for partly sunny skies compared to partly cloudy skies, get to know your favorite source for weather and see what the sky looks like when it says partly cloudy or partly sunny.  You should be able to figure out what category the meteorologist who made the forecast falls in!

Big thanks to "The Media Mind" who provided the inspiration for this post after asking about this in the comments of my last blog post.  If you have a weather question you want answered, comment below and I'll do my best to answer it in a future post!

What's The Difference Between Freezing Rain, Sleet, and Snow?

Sticking with the winter weather theme, I'm going to break down the difference between the three types of winter precipitation: freezing rain, sleet, and snow.  Technically, there are four types of winter precipitation, because it can still just rain during winter!  But everybody knows what rain is, so for this post we'll leave it out.

Freezing Rain

This is a tricky one, because its name is confusing.  A friend of mine said he saw tiny ice pellets falling on the ground around him and called it freezing rain.  If ice is falling from the sky, then yes freezing rain seems like the perfect thing to call it!  But this is in fact sleet, not freezing rain.  Freezing rain is when liquid precipitation falls from the sky and freezes upon contact with the ground, roads, cars, or any other object.  If it's raining outside but you notice patches of ice forming on the ground, that's freezing rain.  Freezing rain occurs when the surface is colder than the atmosphere above.  The surface or object the rain lands on must be at 32 degrees or below to cause the transition from liquid to ice.  However, the air above the surface has to be above 32 degrees for a significant distance in order for the rain to still fall as a liquid.  So, the more accurate term for freezing rain would be "rain that freezes on the surface," but obviously people would get tired of saying that all the time!

Sleet

This is the one that my friend saw falling that day!  Sleet is like hail, only smaller and falls when it's cold, not during a thunderstorm.  If the ice is smaller 0.2 inches in diameter and it's cold outside, it's sleet; bigger than 0.2 inches and warm outside, it's hail.  When the ice that's falling is that tiny, you don't have to worry about it denting your car, but it can still make for very slick roads.  Sleet starts as snow high up in the atmosphere, but if the snow passes through a layer of warm air, it will melt.  If this raindrop then enters another layer of cold air, it will partially refreeze and arrive at the surface as an ice pellet rather than a snowflake.

 

Snow

This is of course the most famous type of winter precipitation and can be common or uncommon depending on what part of the country you live in.  Rather than falling as tiny balls of ice like sleet, snow falls as tiny ice crystals of all shapes, though they typically feature hexagonal symmetry.  Snow can form at any temperature below freezing in the atmosphere, but you typically don't see as much snow formation in extreme cold (below 0 F) because there is usually not enough moisture present.  For snow to reach the surface, the snowflake must not fall through any part of the atmosphere warmer than 32 degrees...as a general rule.  This is why in the southern U.S. snow is so uncommon, because it is rare for the entire atmosphere to be this cold.  However, if the atmosphere is cold enough, snow can still fall when it's above freezing at the surface.  That's because a snowflake can fall for about 1,000 feet in slightly above freezing conditions before completely melting.  If it's warmer than 41 degrees outside though, it's just too warm for snow.

So there's the difference between the three types and hopefully you now have a better idea of just how they form.  Forecasting has improved greatly, but precipitation type is still difficult to predict.  A few degrees difference at any layer of the atmosphere can have a dramatic effect on what type of precipitation falls.  So the next time your meteorologist says it will snow and you instead see sleet falling from the sky, try not to get too angry :) 

Why do You See Your Breath on Cold Days?

We all know that we breathe in oxygen and breathe out carbon dioxide.  But CO2 is not all that we breathe out.  The air inside of our lungs and mouth are very moist and some of this moisture travels outside our bodies in the form of water vapor when we breathe out.  Most of the time we don't notice this, but we can clearly see it when it's cold outside.  That's because when the outside air temperature is cold enough, the water vapor we breathe out is forced to change from a gas to a liquid through the process of condensation.  This is the same process that forms clouds in the skies above, so you're essentially making your own personal cloud just by breathing outside on a cold day!

So how cold does it have to be to make your own cloud?  Well it's not an easy answer because there are a couple of factors involved.  Not only is it dependent on the temperature outside, but also on the humidity.  When you breathe out, your warm, moist breath mixes with the colder, drier air outside.  The combination of your breath and the outside air must reach 100% relative humidity in order for you to see your breath.  100% relative humidity can be reached by lowering the temperature or raising the humidity.  You raise the humidity by breathing out, but if the outside air is warm or really dry (low relative humidity or dew point) it is less likely that you'll see your breath.  If the air outside is more humid, you can see your breath at higher temperatures than you would if the air was dry.  This is why you only sometimes see your breath when temperatures are in the 50s or upper 40s.  If the relative humidity is already above about 50% at these temperatures, the moisture in your breath should be sufficient to bring the mixed relative humidity to 100%.  If the outside relative humidity is under 50% though, even the addition of your moist breath may not be enough to reach 100% relative humidity.  You can even see your breath at 60 degrees, but this is uncommon, as the outside air would have to be at 80% relative humidity or higher to start with which is pretty muggy.

If the air temperature is cold enough though, you are guaranteed to see your breath.  This is right about 45 degrees.  Below this temperature, no matter the outside humidity, your breath will likely supply enough moisture to saturate the air around it and cause the formation of a cloud. 

Now you have a lot to think about the next time you're pretending to be a dragon!

Have a weather related question you'd like me to answer?  Comment below or hit me up on Twitter and I'll be happy to answer your question in a future blog post!