Twister Tech: 5 Ways to Spot Tornadoes Early

The first step is knowing what's coming
Camille Seaman

A More Targeted Warning System

Traditionally, whether a tornado shows up one mile away or thirty, if it's in your county, a siren goes off. But rarely is an entire county at risk, which means that people become accustomed to hearing the siren without seeing a tornado. After a few false alarms, it's easy to stop taking the sirens seriously. To combat this, in 2007 the National Weather Service began targeting polygons, geographic areas as much as 80 percent smaller than entire counties. But many counties didn't have the necessary technology, and county-wide sirens continued. WeatherWarn is a simple solution: a software-based siren controller that automatically activates the correct sirens. It also works with smartphones and social media for areas that are not covered by sirens.

A New Doppler

The Doppler radar system used by the weather service since the 1990s had a limitation: It was one-dimensional. The microwaves it sent out were all oriented horizontally, which meant the system could determine if precipitation was light or heavy, but it could not tell you if that precipitation was rain or snow. In 2013 the weather service upgraded all its equipment to dual-polarization Doppler radar, which uses microwaves oriented in both directions. Coupled with enhanced computer processing to handle the additional data, the weather service radar system can now determine the size and shape of exactly what is in the air.

Tornadoes release built-up pressure in the atmosphere

The Power of Sound...

Because radar works by bouncing off things, it's hindered when hills, trees, and other nonweather objects get in the way. As an alternative, infrasonic arrays measure super-low-frequency sounds, such as the signature wind action of -tornadoes. Those sound waves can travel very far, allowing severe storm activity to be observed from more than 600 miles away.

...And Lightning

Research suggests lightning occurs frequently in developing tornadoes, so scientists are using networks of electrical sensors called Lightning Mapping Arrays to meas-ure the radio-frequency impulses generated by lightning. By pinpointing lightning's location, data can be returned in as little as one minute, as opposed to five to ten for radar.

The Simulator

In 2014 Leigh Orf, a professor of atmospheric science at Central Michigan University, and his team presented the first-ever 3D simulation of an EF5 tornado. The simulation provides a way to study a storm in great detail and from any perspective, which cannot be done with live storms. The better you can understand a fake storm, the easier it is to predict a real one.

Three crazy ways to prevent tornadoes

Tornadoes release built-up pressure in the atmosphere. If we could eliminate them, the atmosphere would have to find another, possibly even more destructive, form of release. But that hasn't stopped people from trying.

Tornado Walls

Theory: Walls 1,000 feet high and 150 feet wide would disrupt the air movement that allows tornadoes to form.

Problem: A simulation found that the walls needed to be more than 8,000 feet high to be effective.

Cloud Seeding

Theory: Seeding a developing storm would cause dissipating precipitation.

Problem: You can't prove that a storm acted the way it did because of seeding, so there is no way to prove its efficacy.

Supercells generate energy on the scale of nuclear warheads. Which would get a little expensive


Theory: Removing the cold air of a tornado by heating up the storms with microwave-shooting satellites.

Problem: Supercells generate energy on the scale of nuclear warheads. Which would get a little expensive.

How to spot a tornado

Camille Seaman

On Land

The first sign is thunderheads: puffy cumulus or cumulonimbus clouds. The wall clouds and funnels will form right beneath them, so check there for any organized rotation. Watch the storm base closely, and look for persistent lowered areas—the lower they are, the better the chance of a tornado. Another good sign is if the winds are warm and blowing toward that base. Look for any motion or quick changes around a flat, lowered area protruding from the storm base, called a beaver tail. Watch the terrain beneath the funnel cloud for any dust or debris that gets kicked up, or for rapidly moving cloud filaments along the ground. In some storms the lightning and thunder will get close, frequent, and loud for five minutes, and then just shut off. That's when the storm gets serious about making a tornado.

With thanks to William Reid, storm chaser.

On Radar

Doppler sends out microwaves that bounce off objects, reporting reflectivity (the presence of weather) and velocity. The first indicator is a hook echo (pictured). On a reflectivity map, it shows up as a hook-shaped formation at the storm's southeast corner, opening toward the east. That signifies precipitation wrapped around a column of warm air. The second sign is a velocity couplet. On a velocity map, you'll see winds moving away from the radar adjacent to winds moving toward it. Because radar typically displays away movement with red and toward movement with green, this looks like adjacent red and green coloration—like Christmas lights. When both a hook echo and a velocity couplet appear on radar readouts, it doesn't necessarily mean there will be a tornado, but it does mean it's time to put out a warning.

With thanks to Steven DiMartino at ­

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