Most tornado injuries and casualties are not actually caused by the high wind speeds, but rather by flying debris that the storm picks up and hurls through the air at incredibly high speeds. As the touchdown of a funnel cloud can cause massive devastation and damage in only a few minutes, being able to quickly and safely access a shelter is of paramount importance to residents who live in the path of these severe storms. In this week’s “TechKnow,” contributor and mechanical engineer Shini Somara explores new technology that could help determine what kind of shelters are built in the future.

TechKnow contributor Shini Somara reviews blueprints for tornado storm shelters.

Underground shelters versus aboveground shelters and safe rooms The National Oceanic and Atmospheric Administration (NOAA) states that “being completely underground is the best place to be in a tornado.” Underground shelters fulfill NOAA’s two most important requirements to staying safe in a tornado: being as low to the ground and putting as many barriers between yourself and the outdoors as possible. For this reason, underground shelters and basements remain the number one option when seeking shelter in a severe storm or tornado. Recently, some experts have been touting aboveground shelters, or safe rooms, as an equally safe (and in most cases, less expensive and more accessible) alternative to underground shelters. These shelters are built using the observed principles that small, interior rooms like bathrooms and closets are sometimes the only parts of a structure that remain standing after a tornado. Reinforced walls protect inhabitants from flying debris, and the shelters can be anchored into the foundation of the house.

The National Wind Institute at Texas Tech University tests how aboveground shelters could stand up to tornadoes’ high winds and flying debris.

One major benefit of in-home aboveground shelters or safe rooms is preventing residents from having to go outside (and risk being hit by debris) to seek refuge in an underground shelter. Other underground shelter risks include flooding and inhabitants becoming trapped underground by debris. In the wake of the EF-5 tornado that hit Moore, Okla., in May of 2013, researchers found that all 16 aboveground shelters or safe rooms that were in the path of the storm survived, and in most cases were the only part of the structure to remain standing.

Read more: “Severe Weather Safety and Survival” -NOAA

“Oklahoma tornadoes: Aboveground shelters stood up in face of EF-5 Moore tornado” -NewsOK

“Can You Really Hide From a Tornado?” -AccuWeather





Schools as shelters The devastating May 2013 tornado in Moore, Okla., destroyed or severely damaged three schools in its path, none of which featured tornado shelters or safe rooms. In fact, despite the state’s location in the middle of “Tornado Alley,” more than 60 percent of Oklahoma’s public schools have no shelter, and of the ones that do, less than half are built to withstand 250 mph winds. The controversy over building shelters in Tornado Alley schools is not whether they are necessary, but rather debate over the cost of how stronger shelters should be built. "Unless there is a basement (in which case a shelter is not necessary), it is probably impractical for to build a school that is safe in 300 mph gusts,” says Mike Smith, Senior Vice President and Chief Innovation Executive of AccuWeather Enterprise Solutions, using the old Fujita scale to estimate wind speeds. “I would build them up to F-3 (162 to 209 mph), which should be adequate since the mathematical odds of F-5 winds hitting a school are very low.”

Wall connections in the new Oakdale Elementary gym/safe room aim to prevent tornadoes from blowing the roof off.