Tag Archives: tornadoes

Late Fall Tornado Outbreak in the Midwest

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Severe weather, including a massive series of tornadoes, roared across the American Midwest on Sunday.  These powerful storms caused widespread damage and knocked out power to tens of thousands of people.  Numerous injuries and at least eight fatalities have been reported so far.

NWS survey teams are currently on the ground evaluating the damage, but early reports estimate that several dozen twisters touched down across seven states. The two strongest have been preliminarily rated EF-4, the second highest ranking on the Enhanced Fujita Scale.  With winds raging between 166 and 200 mph, they devastated the towns of Washington and New Minden, both in Illinois.  Officials say these were the strongest and deadliest November tornadoes on record in the state.

This historic outbreak was the result of an explosive mix of atmospheric conditions, including instability generated by the collision of a cold front with warm, moist air moving up from the south.  In addition, the combination of a powerful jet stream aloft and a strong area of low pressure near the ground – with winds blowing in the opposite direction – helped generate spin in the atmosphere.

While autumn, the so-called second season for tornadoes, has been known to produce severe storms, they usually occur in the warmer climates of the Southeast and Gulf Coast. Twisters further north, especially powerful ones, are very rare for this time of year.

Damage from tornadoes near washington, IL

Damage from tornadoes near Washington, IL                                                                                     Image Credit: A. Koury

NOAA

Image Credit: NOAA

 

A Week of Wild Weather Across the U.S.

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Extreme weather battered much of the United States this past week.  From heavy snow and tornadoes in the plains to a tropical storm in the Gulf and blustery Santa Ana winds in California, this country saw it all in just six days.

Starting on Tuesday, a pre-season winter storm dumped massive amounts of snow across Wyoming and South Dakota. Some places, like Deadwood, SD received as much as 48 inches.

On Wednesday, the NWS named Tropical Storm Karen. Moving north across the Gulf of Mexico, it threatened coastal communities from Louisiana to Florida with heavy rain and storm surge flooding.  Luckily, however, the storm was downgraded to a rainstorm by the time it came ashore.

By Friday, the cold air that produced the blizzard in the northern plains collided with warm moist air to the east and unleashed severe thunderstorms across the region.  They, in turn, spawned numerous tornadoes.  One of the hardest hit areas was Wayne, NE where an EF-4 twister with winds measured up to 170-mph tore through the town.  While widespread property damage and numerous injuries were reported, there were no fatalities.

Over the weekend, powerful Santa Ana winds blasted southern California with gusts reaching 90-mph in some areas.  These warm, dry winds helped fuel a large wildfire in San Diego County.

While extreme weather events are not unusual in this country, having such a large number and wide variety happen more-or-less at once is very rare.

Widest Tornado on Record Strikes El Reno, Oklahoma

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A massive twister struck the town of El Reno, OK on Friday.  Measuring 2.6 miles across, it was the widest tornado ever recorded.

According the National Weather Service, the winds of this violent storm reached as high as 295 mph.  On the ground for forty minutes, it traveled more than sixteen miles. This powerful twister and the flooding rains associated with it claimed the lives of nineteen people, including three storm chasers.

Initially classified as an EF-3, the NWS upgraded this storm to an EF-5 – the highest ranking on the Enhanced Fujita Scale – after evaluating the damage. This was the second EF-5 tornado to strike Oklahoma in less than two weeks.  The other leveled the nearby city of Moore.

Since 1950, according to NOAA’s Storm Prediction Center, sixty EF-5/F-5 tornadoes have struck the United States.  Eight of these touched down in Oklahoma.

Devastating Tornado in Oklahoma

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Barreling through the Oklahoma City area on Monday afternoon, a powerful tornado leveled the suburb of Moore, OK.  It claimed the lives of twenty-four people and injured hundreds of others.

The National Weather Service has rated this deadly twister as an EF-5.  That is the highest ranking on the Enhanced Fujita Scale.  On the ground for forty minutes, with winds in excess of 200 mph, this powerful storm cut a path of destruction seventeen miles long and more than a mile wide.

Located in the heart of tornado alley, this community is no stranger to severe weather events.  Moore was in the path of the infamous tornado of May 3, 1999 that set the record for the fastest wind speed ever recorded, 318 mph.

As it has in the past, this town is planning to rebuild.  The price of which, according to current insurance estimates, is expected to exceed two billion dollars.

A field of debris from Monday's EF-5 Tornado in Moore, OK.

A field of debris from Monday’s EF-5 Tornado in Moore, OK.

Image Credit: Oklahoma County Sheriff’s Office/ABC

Deadly Tornado Outbreak in Texas

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A swarm of tornadoes barreled across northeastern Texas on Wednesday evening.  These powerful storms caused widespread damage and claimed the lives of at least six people.

The National Weather Service, in its preliminary assessment, reported that sixteen twisters touched down near the Dallas-Fort Worth Metroplex, one of the largest metropolitan areas in this country.  The strongest storm in this outbreak was rated an EF-4, the second highest ranking on Enhanced Fujita Scale. With winds ranging from 166 to 200 mph, it devastated the town of Granbury, TX. Another hard hit area was Cleburne, TX, where an EF-3 storm is reported to have cut a path one-mile wide through part of the city.

Tornadoes, nature’s most violent storms, are generated by severe thunderstorm activity.  That said, not all thunderstorms produce twisters.  They need something to set the lower atmosphere into a twisting motion.  In this case, that was warm, humid air moving north from the Gulf of Mexico that collided with hot, dry air blowing in from the west.

Texas Tornado

Texas Tornado

Image Credit: WHNT

NYC Tornado Watch

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A tornado watch is in effect for New York City today until 9 P.M. This means that isolated tornadoes could possibly develop as severe thunderstorms move through the area.

Tornadoes, historically, have been rare events in NYC.  In recent years, however, they have been happening more frequently.  Of the eleven twisters that have touched down in the city since 1950, seven have occurred in the past nine years.  In fact, two roared through the boroughs of Brooklyn and Queens earlier this month. Many experts consider this increase in severe weather to be an indication of a changing climate.

Note: Tornado ratings moved from the Fujita Scale (F) to the Enhanced Fujita Scale (EF) in 2007.  Chart Data: NWS

Two Tornadoes Touchdown in NYC

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Severe weather battered much of the northeastern United States this weekend.  Here in New York City, strong thunderstorms spawned two confirmed tornadoes.

The first twister touched down in Breezy Point, Queens.  With wind speeds of 70 mph, it was rated an EF-0 on the Enhanced Fujita Scale.  Minutes later, a more powerful EF-1 storm tore through the neighborhood of Canarsie, Brooklyn.  Winds blowing at 110 mph ripped branches from trees and damaged numerous homes.  Luckily, no fatalities have been reported.

Tornadoes are rare in New York City, but they can form anywhere given the proper conditions.  This weekend, an intense cold front overtook the city’s existing warm, humid air mass, which created an atmosphere unstable enough to power these violent storms.

How Tornadoes Form

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Generated by severe thunderstorm activity, tornadoes are nature’s most violent storms. Scientists do not know exactly what causes them, but atmospheric instability and wind shear are important contributing factors.

Instability in the atmosphere is created when a warm, humid air mass meets a cool, dry air mass.  Through the process of convection, this encounter allows warm air to rise easily and produce thunderstorms.  The greater the instability, the stronger a thunderstorm can become.

Wind shear occurs when there is a localized change of wind speed and direction.  When surface winds blow in one direction and upper level winds in another, the air in-between is set in a horizontal rolling motion.  The updraft of the thunderstorm can then tilt the rotating air into a vertical position.  When that vortex extends from the cumulonimbus cloud to the ground, a tornado is born.

Tornadoes can occur anywhere in any season, but are more typical in the spring and summer months in the United States.  According to NOAA, approximately 1,200 tornadoes touch down in this country every year.

Severe Weather: Watches and Warnings

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Severe weather can happen anytime of the year, given the proper conditions.  This past weekend, for example, unstable air and wind shear combined to send tornadoes roaring through America’s heartland.

Any meteorological event that can cause property damage and loss of life is categorized as severe. It can come in a variety of forms, depending on location and season.  High winds, strong thunderstorms, tornadoes, wildfires, dust storms, hurricanes, floods, and blizzards are all examples of severe weather that occurs in the United States.

When any severe weather event is in the forecast, it is important to understand the difference between the various alerts issued by the National Weather Service.  They include advisories, watches, and warnings.  All should be taken seriously.

  • Advisory:  An “advisory” is issued when significant, but not severe, weather conditions are likely to occur. Residents should exercise caution.
  • Watch:  A “watch” is issued when dangerous weather conditions are possible over the next several hours.  They generally cover a large geographic area.  Residents should be prepared to take action.
  • Warning:  A “warning” is issued when dangerous weather is imminent or already occurring.  They cover a smaller, more specific geographic area.  Residents should take action immediately.

Texas Tornado Outbreak

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Tornadoes swept across northeast Texas yesterday afternoon.  Widespread damage and numerous injuries have been reported, but luckily no fatalities.

So far, the National Weather Service has confirmed that eleven twisters touched down in the Dallas-Fort Worth metroplex, the ninth-largest metropolitan area in this country. The strongest storm in this outbreak was rated an EF-3 on the Enhanced Fujita Scale. It tore through the Dallas suburb of Forney, TX with winds of up to 150 mph.

Video taken during this outbreak shows the incredible power of a tornado’s winds, both horizontal and vertical. The footage of 8-ton tractor-trailers being lifted over one hundred feet in the air and tossed around like toys is unforgettable.

It is sadly coincidental that this devastating storm occurred on the anniversary of the Super Outbreak of 1974, the most violent tornado outbreak in U.S. history.

Tractor-trailers being sent skyward by the lifting power of a tornado near Lancaster, TX

Image credit: KXAS