9 Powerful Facts About Derechos

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iStock

Think about the worst thunderstorm you've ever witnessed. Having trouble remembering the specifics? That's because in the summertime, thunderstorms are a relatively mundane occurrence, even for those of us with a flair for exaggeration. There are some storms, though, that rise to a whole new level; a derecho is one of those storms. Derechos can sweep across entire states and leave behind more damage than a tornado, yet they're relatively unknown by anyone other than weather enthusiasts.

1. DERECHOS ARE MASSIVE.

A squall line or bow echo is a group of thunderstorms that are connected to one another and take on a bow-shaped look on weather radar. A squall line that forms under the right conditions can mature into a small but powerful storm system in its own right, developing tiny high- and low-pressure centers that can help drive the thunderstorms for hundreds of miles.

A radar image of an intense derecho in Missouri on May 8, 2009.Gibson Ridge

A derecho is a long-lived squall line that produces a swath of wind damage more than 200 miles long. People who go through derechos sometimes compare them to hurricanes because of the strength of the winds and the amount of damage they leave behind. The term derecho, pronounced “duh-RAY-cho,” comes from the Spanish word for “straight,” a reference to the winds that make these storms so powerful.

All derechos are squall lines, but not all squall lines turn into derechos. The term derecho only applies when large amounts of land area see damage from a storm. But regular squall lines are nothing to sneeze at: A system that only affects three counties can be just as strong as one that affects three states.

2. DERECHOS GET THEIR BITE FROM COLD AIR.

What distinguishes a squall line from a normal thunderstorm is how the updraft and downdraft develop. The thunderstorms in a squall line form along the leading edge of the pool of cold air dragged to the ground by the downdraft. This dome-shaped cold pool tilts the updraft of warm, unstable air, preventing the updraft from suffocating on cool air. Air inside the cold pool beneath the storms can begin to circulate due to upper-level winds and friction with the ground, creating a dangerous feature called a rear-inflow jet. This jet of strong winds forms a few thousand feet above the ground and races toward the front of the thunderstorms, where it's shoved into the ground at the leading edge of the squall line, creating a derecho's signature winds.

3. STRAIGHT-LINE WINDS MAKE THEM DANGEROUS.

Tornadoes get all the attention during storm season, but the truth is that straight-line winds can cause just as much damage as a tornado, but over a much wider area than a tornado could ever cover. Just as the name suggests, straight-line winds hit the ground and move in the same direction, sometimes blowing for more than five minutes. The sudden impact and long duration of these winds can put serious stress on trees, buildings, and anything not tied down to the ground.

4. A DERECHO CAN CAUSE AS MUCH DAMAGE AS A TORNADO.

The aftermath of many derechos looks like what you'd see after a hurricane makes landfall. Some people even swear that they were hit by a tornado, not believing that a severe thunderstorm could make that big of a mess. The straight-line winds in a derecho can climb as high as 100 mph—strong enough to rip the roofs off of homes and completely destroy structures like barns and silos. Even a derecho that just barely qualifies as one can leave behind thousands of downed trees, long-lasting power outages, and annoying and costly cosmetic damage to homes and businesses.

5. SOME ARE MORE SERIOUS THAN OTHERS.

There are two different types of derechos. The most dangerous type is a progressive derecho. This is the kind of storm you see in the summer that speeds across entire states and leaves tornado-like damage in its wake. A serial derecho forms along a cold front. What a serial derecho lacks in focused damage it can make up for in the sheer amount of land exposed to severe wind gusts. It's possible for the length of a serial derecho to stretch from the Great Lakes to the Gulf of Mexico as it moves from west to east. Serial derechos are most common during the fall and winter months.

6. HEAT WAVES BREED DERECHOS.

A relentless summertime heat wave can trigger multiple derechos in one week if conditions are just right. A high-pressure system that causes a brutal heat wave during the summer is sometimes called a “ring of fire” by meteorologists. The northern edge of one of these hot high-pressure systems can serve as the point for a progressive derecho to form. Once the derecho has developed, it races east or southeast along the outer edge of the high-pressure system until it dissipates or reaches the Atlantic Ocean.

7. THE CLOUDS CAN LOOK TERRIFYING.

The ominous clouds ahead of a derecho can tell you pretty quickly that this is no ordinary storm headed your way. Derechos are home to the most incredible shelf clouds nature can produce. A shelf cloud is a thick cloud that juts down from the sky, like a shelf hanging beneath the bottom of the storm. These clouds form when warm air rises up and condenses over the top edge of the cold pool that drives these storms. Shelf clouds are quite common, but the vivid shelf clouds in derechos are a spectacular, albeit scary, sight to see.

8. THE WIND COMES ON SUDDENLY.

One of the reasons derechos (or any intense squall line, really) can wreak such havoc is because they come on suddenly. There usually isn't much of a buildup to the strongest winds before they hit. Conditions can go from calm to chaos in a matter of seconds. The abruptness with which the winds can hit can even snap off the tops of trees as if they were chopped down by hand.

9. THERE ARE A FEW DERECHOS EVERY YEAR.

Derechos are most common in the central United States, but they can form just about anywhere around the world that experiences severe thunderstorms. Most derechos go unnoticed by those not directly affected by the storm, but some can have such a large impact on populated areas that they make national news.

One such storm was the derecho that formed on June 29, 2012. The storms started in Indiana, grew into a monstrous squall line in Ohio, and blew across the Appalachian Mountains virtually unimpeded before continuing on to the Atlantic Ocean. The Storm Prediction Center received hundreds of reports of wind damage after the storm. Washington D.C. and its suburbs were particularly hard-hit by the storm's winds. The derecho left millions without power, some for weeks after the storm, and multiple people lost their lives as a result of falling trees.

Looking to Downsize? You Can Buy a 5-Room DIY Cabin on Amazon for Less Than $33,000

Five rooms of one's own.
Five rooms of one's own.
Allwood/Amazon

If you’ve already mastered DIY houses for birds and dogs, maybe it’s time you built one for yourself.

As Simplemost reports, there are a number of house kits that you can order on Amazon, and the Allwood Avalon Cabin Kit is one of the quaintest—and, at $32,990, most affordable—options. The 540-square-foot structure has enough space for a kitchen, a bathroom, a bedroom, and a sitting room—and there’s an additional 218-square-foot loft with the potential to be the coziest reading nook of all time.

You can opt for three larger rooms if you're willing to skip the kitchen and bathroom.Allwood/Amazon

The construction process might not be a great idea for someone who’s never picked up a hammer, but you don’t need an architectural degree to tackle it. Step-by-step instructions and all materials are included, so it’s a little like a high-level IKEA project. According to the Amazon listing, it takes two adults about a week to complete. Since the Nordic wood walls are reinforced with steel rods, the house can withstand winds up to 120 mph, and you can pay an extra $1000 to upgrade from double-glass windows and doors to triple-glass for added fortification.

Sadly, the cool ceiling lamp is not included.Allwood/Amazon

Though everything you need for the shell of the house comes in the kit, you will need to purchase whatever goes inside it: toilet, shower, sink, stove, insulation, and all other furnishings. You can also customize the blueprint to fit your own plans for the space; maybe, for example, you’re going to use the house as a small event venue, and you’d rather have two or three large, airy rooms and no kitchen or bedroom.

Intrigued? Find out more here.

[h/t Simplemost]

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7 Facts About the Hurricane Highway

Hurricane Earl (top) and Hurricane Fiona (bottom) pummel the U.S. coast and Caribbean islands.
Hurricane Earl (top) and Hurricane Fiona (bottom) pummel the U.S. coast and Caribbean islands.
NOAA/NASA GOES Project // Public Domain

Autumn is the peak of hurricane season, also known as Cape Verde season, after the islands where the so-called "hurricane highway" originates. Here are seven facts about this awesome—and sometimes deadly—weather phenomenon.

1. The hurricane highway begins near the African coast.

The Cape Verde Islands, located off the northwest coast of Africa, are where the hurricane highway starts. Thunderstorms destined to become hurricanes often form into a tropical depression near the islands, slowly organizing and strengthening over the following week as the system moves toward the Caribbean. These storms have a long time to get their act together, but they also have to cover a lot of distance without losing their power to reach the East Coast as a hurricane. Some storms are able to thrive with little wind shear, ample warm water, and moist air, while others starve and dissipate if they encounter cooler waters and strong winds, or ingest dry, dusty air blowing off the Sahara Desert.

2. An easterly jet stream gives rise to the hurricane highway.

It’s hard to imagine from North America that a couple of thunderstorms on another continent thousands of miles away can swirl up into a monstrous storm, but it happens almost every year. The extreme temperature gradient between the blistering heat of the Sahara Desert and the more temperate climate of the savanna to its south creates an easterly jet stream that triggers clusters of showers and thunderstorms. These clouds then move from east to west, emerging off the western African coast near the Cape Verde Islands. Every year, the right conditions turn a handful of these localized storms into tropical storms that make their way across the Atlantic.

3. The biggest hurricanes start with the smallest storms on the hurricane highway.

Hurricane Andrew was a Category 5 hurricane when it made landfall in Homestead, Florida.Xanxz/NOAA, Wikimedia Commons // Public Domain

Hurricanes, cyclones, typhoons—these are all names for the same force of nature, like Hurricane Andrew, which hit the East Coast in 1992. Cyclones like Andrew don’t just form out of thin air. All tropical cyclones require a relatively tiny “nucleus” of thunderstorms in order to develop. When the air and water temperatures are right, these groups of thunderstorms sometimes spin up into a fierce low-pressure system capable of causing a lot of damage. We see lots of these seedling thunderstorms over the ocean every year, but only a small number of them become hurricanes.

4. Hurricanes form in different places in different months.

Where a tropical storm or hurricane begins its trip across the ocean depends on what time of the year it forms. Storms that form early in the season usually get their start from thunderstorms or cold fronts that stall over the water very close to land; almost all of the storms that form in the Atlantic in June come to life within a few hundred miles of land. When we reach the peak of hurricane season, though, they start to form farther and farther out in the ocean—all the way out to the shores of Africa.

5. Fall is the peak of hurricane season on the hurricane highway.

Hurricane season in the Atlantic Ocean runs from June 1 through November 30. Storms are most common during that six-month stretch of the year, but sometimes they can form earlier or later too. That said, the period between the middle of August and the middle of October is typically the climatological peak of the season. That’s because, as the ocean water gets warmer, the atmosphere becomes conducive to vigorous storms, increasing the risk for hurricanes and tropical storms.

6. Cape Verde hurricanes can easily land in the record books.

This image shows the tracks of all tropical cyclones recorded in the Atlantic Ocean between 1851 and 2014.
Dennis Mersereau

Tropical waves traveling west from the coast of Africa in the middle of the summer are the culprits behind some of the worst hurricanes we’ve experienced in the United States. For example, on August 8, 2005, a small tropical wave emerged off the coast of Africa, soon becoming Tropical Depression 10. That depression would fall apart a few days later, but its remnants kept moving toward the U.S., redeveloping into a new tropical depression over the Bahamas on August 23. That new tropical depression became Hurricane Katrina, the costliest hurricane to ever strike the United States.

It’s a similar story for many—but not all—major hurricanes in recent history. Hurricanes Andrew, Dennis, Ivan, Isabel, and Ike were all Cape Verde–type storms that sprang to life thousands of miles away from where they would ultimately wreak havoc.

7. Strong hurricanes can still form in other places in autumn.

While the far eastern part of the Atlantic Ocean is a hotbed of activity this time of the year, it’s not the only place you need to watch if you live near the coast. Storms that form close to land can quickly spin themselves into catastrophe. Hurricane Sandy formed just south of Jamaica and hit New Jersey in a matter of days in 2012. A tropical depression that developed east of Florida on September 18, 2005, exploded into Hurricane Rita just three days later, with 180 mph winds—the most intense storm ever recorded in the Gulf of Mexico.

Meteorologists are currently predicting an above-average hurricane season in 2020. It may be worth preparing: NOAA suggests gathering a few key disaster supplies to have on hand, getting an insurance check-up, and locating the safest high ground.