Need to Know: How tornadoes can destroy a town in mere minutes

On this week’s “TechKnow,” Dr. Shini Somara travels to the part of the U.S. known as “Tornado Alley” to learn more about the devastating effects of tornadoes and how scientists and engineers are working to keep people safer from these storms. Unlike hurricanes and other severe storms, the short-lived and seemingly random nature of tornadoes has made them some of the country’s most devastating natural disasters.

Here are four things you should know about tornadoes and the damage they cause:

1. Tornadoes can touch down anywhere

“Tornado Alley” states such as Kansas, Nebraska, Texas and Oklahoma are perhaps most well-known for their frequent twisters, as they sit on what weather experts refer to as the “dryline”—the region where moist air from the Gulf of Mexico meets dry southwestern air, creating the perfect conditions for tornado-producing thunderstorms. Texas averages the most tornadoes per year, at around 125.

However, there are many other states east of the Rocky Mountains that experience at least as many tornadoes per square mile in a year as “Tornado Alley” states. Florida has the most tornadoes per square mile per year, and Iowa, Indiana, Illinois and Louisiana also experience at least as many tornadoes as their more midwestern counterparts. In fact, every single U.S. state has recorded a tornado.

Read more: “What and where is Tornado Alley?” -The Weather Channel

2. The way experts track tornadoes is about to change

Weather experts track tornadoes using traditional radar technology which sends radio bursts to measure the size, shape, and direction of storms and funnel clouds. The system currently used by the National Weather Service consists of about 150 radar antennas that can track storms up to 100 miles away.

Recently, a more advanced radar system has been developed by a group called CASA (Collaborative Adaptive Sensing of the Atmosphere), a collective formed by several universities and funded by the National Science Foundation. CASA’s radar aims to augment the current radar system by utilizing smaller antennas on building and cell phone towers. Having more antennas allows for more frequent updates (about once a minute compared to the NWS’s five minutes) and a better picture of the storm.

Read more: “Advanced Tornado Technology Could Reduce Deaths” -NPR

3. The EF scale ranks tornadoes based on both wind speeds and damage

The Enhanced Fujita (EF) scale is used to rank tornadoes on a scale from zero to five based on wind speeds and estimated damage, unlike the Hurricane Severity Index (HSI) which ranks storms based on wind speeds and area of the storm with no accounting for damages.

The EF scale uses a “three second gust” wind speed estimate based on the degree of damage to environmental indicators such as buildings and trees.  National Weather Service experts observe damage to multiple indicators and compile that information to assign an official EF Scale rating to each individual tornado.

Read more: “The Enhanced Fujita Scale” -NOAA

4. Tornadoes can cause billions and billions of dollars in damage

Tornado destruction comes from two primary factors: the high-powered winds produced by the storm and flying debris that is picked up by these winds. Scientists have long-since disproved the myth that pressure imbalances caused by tornado winds make homes and buildings “explode.” In reality, high winds rushing into a home or building through an opening can force the roof off and the walls to collapse outward, creating the false appearance of an explosion.

The destructive storm that hit Moore, Okla., in May of 2013 ended up being the third costliest tornado in U.S. history, with about $2 billion in damage (all past storms were adjusted to account for inflation). The tornado that devastated Joplin, Mo., in May of 2011 is currently the most damaging in U.S. history at almost $3 billion in damage.

Read more:

“Oklahoma Twister Among Five Costliest in History” -CNBC

“12 Twisted Tornado Facts” -LiveScience

“How Tornadoes Work” -HowStuffWorks

Watch “TechKnow,” Sunday 7:30ET/4:30PT on Al Jazeera America.