Natural disasters like earthquakes, floods, hurricanes and tsunamis have long been fodder for Hollywood blockbusters, and so have tornadoes, most famously in the 1996 movie "Twister." Visual effects have come a long way in 18 years, which makes "Into the Storm," the latest installment in the subgenre, a visually stunning experience. But how accurate is it? Director Steven Quale says he strived to ground his people-in-peril epic in reality.

Quale immersed himself in research with YouTube videos of tornadoes and storm chasers, meteorology textbooks and picked the brain of a UCLA meteorology professor "to show the unbelievable, powerful but awe-inspiring power that Mother Nature can create with these tornadoes, up-close and personal like nobody's ever seen before. I wanted to get it as accurate as possible as far as how powerful and destructive these tornadoes can be."

If it seems unlikely that four tornadoes could hit one town in 12-hour period like the film depicts, know that there are multiple tornado outbreaks on the record books. But Quale concedes that "the variety of tornadoes — rope, wedge, and so on — we have happening in a 12-hour period is more of a stretch." He felt validated in depicting a mile-wide EF5 funnel when during post-production news came in of an El Reno, Oklahoma, tornado "2.5 miles wide, the widest ever recorded."

Quale also wanted the movie's soundscape to be as real as possible. "Half the movie-going experience is sound, and when you're in a dark room and you're hearing the rumble of tornadoes approaching, it's that fear and anticipation of it that raises expectations when it finally hits," he explains. "I didn't want lion roars or other sweeteners that are usually added to make it sound bigger than life. We went for as much realism as we could possibly get."

The movie's storm-chasing team travels in armored vehicle called Titus, which is armed with 24 cameras and built to withstand 170 mph winds, and a weather van with state-of-the art equipment. For the former, "We created our own hybrid modified from a Dodge pickup truck," says Quale, adding that the van was outfitted with radar, eight computers, and feeds from Doppler radar and the Weather Channel.

The storm chasers in

The storm chasers in "Into the Storm." (Photo: Warner Bros. Pictures)

The twister turns vehicles of every stripe — and a few cargo jets — into airborne projectiles, all based on real footage, notes Quale, who created these scenes with a mix of practical and computer-generated effects. "We'd have actors working with practical effects in the foreground — the wind and rain near their face is all real — and the tornado in the background is digital. Almost every shot was augmented in some manner with visual effects. For the sequence in the storm drain, we created a wind tunnel. We had two 100 mph fans going at full blast." In the scene where actor Richard Armitage is nearly smashed by a flying pickup truck, "We did all of that for real with a safety harness and wires. The next shot is all-digital, but you can't tell the difference."

Ironically, CGI was necessary to turn unexpectedly sunny skies gray. "I wanted it to look gloomy and overcast, but two thirds of our shooting days were bright and sunny," explains Quale. "So we had to put giant silks up and digitally paint out the sun. It was a time-consuming process but in the end it worked out well."

As for the constant downpour of manufactured rain, it was welcome during the hot days of summer in Michigan, but being perpetually wet quickly turned miserable toward the end of filming when the weather turned cold, notes Quale. He's always had a fascination and obsession with Mother Nature, and it magnified while making the movie, which hits theaters on Aug. 8. "It's almost surreal how different winds interacting can create such devastating energy, power and destruction," he says. "It's humbling to see."

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The other side of the coin

Quale worked hard to find a balance between fact and fiction, so how did he do? Meteorologist Dr. Greg Forbes knows how devastating tornadoes can be. The Weather Channel's severe weather expert studied under Ted Fujita (namesake of the Enhanced Fujita rating scale for tornadoes), and developed the TOR:CON index, which estimates the risk of a tornado on a given day or night in any given area. He has seen their power up close: when he was a child in the Netherlands he witnessed a small twister knock a tree down in his backyard. While he has not seen "Into the Storm," he was able to discuss the tornadoes it portrays, and all the crucial information you need to know about them.

Greg ForbesMNN: Can you explain the differences between the types of tornadoesand why, when and where they're most likely to occur?

Greg Forbes: Tornadoes can take on different appearances, from a narrow rope to a cylinder to a stovepipe to a cone (wide at the top and narrow at the ground), to a wedge (very wide at the ground and at cloud base). Tornadoes come in a variety of intensities, with wind speeds estimated after-the-fact based upon the damage they produce — unless a research mobile Doppler radar nearby gets actual speed measurements. The speeds can range from EF0 (65-85 mph gusts) to EF5 (over 200 mph) on the Enhanced Fujita (EF) Scale. Some tornadoes, called supercell tornadoes, develop from thunderstorms with a strong counterclockwise-rotating updraft at mid-storm altitudes.  Other tornadoes form in zones of shifting winds along the edges of thunderstorm gusts near the ground. Tornadoes are most common from east of the Front Range of the Rockies to the Appalachians and Southeast, but every state has experienced tornadoes. 

How common are EF5 tornadoes? What's the biggest on record? The most intense?

EF5 tornadoes are relatively rare as a percentage of all tornadoes — about a tenth of one percent.  In the 10 years between 2005 and 2014 there have been a total of nine EF5 tornadoes. Four of the 10 years had an F5/EF5, with six of the nine in 2011. The fastest wind speed is not perfectly known, but the Moore, OK tornado on May 3, 1999 had winds measured at 301 mph at about 105 feet above ground. Some credit the El Reno, OK tornado of May 31, 2013 as being the widest, at 2.6 miles, but there may have been some wider than that. The Tri-State (MO-IL-IN) Tornado of March 18, 1925 is the deadliest tornado and is traditionally thought to have carved a 219-mile path. But some researchers think the path may have been shorter--the total due to several tornadoes — and killed 695 people. 

How common are multiple funnels?

Multiple funnels are relatively common. They can be within the same tornado, called "suction vortices."  Or they can be as "satellite" tornadoes orbiting about a larger tornado. 

Are tornadoes becoming more common? Or are they just photographed more?

The total number of reported tornadoes has risen to an average of nearly 1300, up from an average of less than 500 in the 1950s.  But the increase has occurred almost entirely in the weak (F0/EF0) tornadoes that went unreported in decades past.  Meteorologists believe that the increase in reported numbers of F0/EF0 tornadoes arises from several societal factors including:  (1) increased population and urban sprawl; (2) improvements in NWS surveys of tornadoes and cooperation with emergency managers that increases efficiency of tornado reporting; (3) increases numbers of storm spotters, storm chasers; (4) increase in public awareness of tornadoes and dramatic increases in availability of a variety of photo devices and submission of videos to the media and the National Weather Service; (5) development and growth of social media through which tornado information can be shared.

What kind of tornado warning systems are in use now? How effective are they?

The NWS issues tornado warnings that are distributed to the public by a variety of platforms, including:  NOAA Weather Radio; television and radio, social media; smart phones, phone calls and other platforms. Doppler radar and human spotters are the primary tools by which tornadic storms are detected. In the past couple of years the Doppler radars have been upgraded to "dual-Pol" status, and one of the new measurements enables the detection of debris being tossed aloft by tornadoes: Tornado Debris Signature (TDS). This helps add confidence to the Doppler warnings, which, when based solely on winds, are often false alarms.

What's in the pipeline in detection?

The NWS is trying to improve computer models to the point that they can rather accurately predict the motion of severe thunderstorms and their tornadic potential. In the next 10 years this could enable tornado warnings partly based upon forecasts, which could increase the lead time, the time between warning issuance and tornado occurrence, which now averages about 13 minutes.   

Do you have any advice for the public about tornado preparedness — and tornado survival?

Tornadoes can strike at any location and at any time. While there are legends that say, "Tornadoes don't hit here," they are not true. Know where the safe location is in your home and place of work so that you can go there quickly should a tornado approach. If possible, have a helmet there to put on to help protect against head injuries and wear shoes in case you need to climb out into the tornado debris. Mobile homes are not safe in tornadoes, so people living in them would be wise to plan some alternative shelter location ahead of time. Most of all, tornadoes can hit suddenly, so paying attention to the weather forecast daily can lead to an awareness of the relatively few days likely to have the highest chance of a tornado.

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