Sometimes the tornado wins big

kw: book reviews, nonfiction, tornadoes, atmospheric science, meteorology, storm chasers, biographies

I've never chased tornadoes, but I have seen a few. The number is small enough to catalog:

• 1964, August, Cedar Point, Ohio: A squall line spit out seven waterspouts, one after another, that marched out of Sandusky Bay and crossed the Causeway and Chaussee between the amusement park and the city of Sandusky, then dissipated. Waterspouts are seldom stronger than EF0 or EF1.
• 1985, Summer (July?), Rapid City, South Dakota: 4 tornadoes, all probably EF1, touched down in and around the city. I saw two of them. Looking west out my back door, I saw a funnel forming, ran out to take a picture of it, then found it hard to open the door against the wind. My wife called me to the other side of the house. To the northeast, a tornado was on the ground right across the street, tearing up sorghum in my neighbor's field. It was moving east, and no houses were hit. Driving into town the next day, I saw three buildings. Two were untouched; the third, in between the others, had lost its roof, a metal roof which was curled up behind the building. The barbed-wire fence in front of the buildings was full of fiberglass insulation.
• 1990, Summer (August?), Stillwater, Oklahoma: I didn't actually see this one, it was wrapped in rain. I was visiting a friend when my wife phoned to say the tornado siren near our home had gone off—would I please come home? I kidded her, "It sounds like I am safer where I am, but I'll come right now." All the stop lights were not functioning, and nobody else was on the road. As I turned onto the main drag that runs north through town, it began to rain so hard there was soon surf in the middle of the street. When it began to hail, I turned into a parking lot up against a large store, to its south. I tuned to a Tulsa station (the local station was off the air), just in time to hear them say, "We have it on radar, it is crossing Perkins at McElroy." I said to myself, "That is where I am!" The store was on the southeast corner of that intersection. The tornado was actually half a block to my north, taking the top floor from a row of two-story apartment buildings and piling up their A/C units in land to the east. It also broke off a dozen or more power poles around ten feet above ground level, so it was a "skimmer", not quite on the ground yet. I saw all this after the sky cleared, about two minutes after the radio announcement. I made it home safely.
• 1994, June, near Colby, Kansas: We were on our way to Denver from Stillwater. Our son was 7 at the time. Highway I-70 had just hooked northwest, several miles west of Grinnell. Perhaps 10-15 miles ahead we saw a squall line dropping a tornado, which traveled across the road and then dissipated. Another soon followed, and then a third. Then the storm itself broke up. I had slowed down, expecting we might have to stop before getting near the storm. We got to that bit of highway about 15 minutes after the last tornado collapsed and the sky had cleared. There was about a half mile of wet highway, with some torn-up ground on both sides. These were probably EF1 tornadoes. Though that is "weak" compared to the monster EF4 and EF5 storms, an EF1 can still roll a car around until there is too little room left inside for you to stay alive.

What is the tornado scale? The "F" or Fujita Scale was developed by Theodore Fujita in 1971. It was originally a 13-level scale of wind speeds, derived by the formula (V = wind speed in mph):

V = 14.1(F+2)^1.5

Dr. Fujita didn't expect F numbers greater than 5 to ever be used. So far, none has. This formula produces this table of the minimum wind speed for each F number:

• F0 = 40 mph
• F1 = 73 mph
• F2 = 113 mph
• F3 = 158 mph
• F4 = 207 mph
• F5 = 261 mph
• F6 = 319 mph

The "EF" or Enhanced Fujita scale replaced the "F" scale in 2007, with the threshold velocities changed to account for improved research into the kinds of damage caused by various wind speeds. The six thresholds (there is no EF6 or higher) are 65, 85, 110, 135, 165, 200. There is no corresponding formula, but a geometrical analysis indicates to me that a theoretical EF6 region should begin at about 235 or 240 mph and EF7 at about 285-290. This is important for what follows. But let it be said, an EF5 tornado can rip the slab of a house right out of the ground, and even pull some basements up, so there is little point in assigning larger numbers without measurement. When a tornado leaves nothing behind but plowed ground, you're already off the charts!

The Man Who Caught the Storm: The Life of Legendary Tornado Chaser Tim Samaras, by Brantley Hargrove, is a very exciting, fascinating, and ultimately rather sad, biography of Tim Samaras. The author is an excellent journalist, who dug into his subject to the point that he participated in several storm chases with friends of Tim, and witnessed some awesome tornadoes in the process.

Tim Samaras exemplifies the self-educated genius. Classroom study was not for him. With his parents' encouragement, he began taking apart various appliances and electronic devices from an early age. Sometimes he could get them back together. By the time he needed paying work, he was such a valuable instrument inventor and repairman that he was hired in spite of having no college. He cut his professional teeth designing and running instrument packages that could, for example, measure the blast force of two tons of ANFO, the explosive that Timothy McVeigh used to destroy the Murrah Building in Oklahoma City in 1995 (an explosion I felt from 75 miles away).

Tim was also a weather fanatic, and took to storm chasing very early on, teaching himself the meteorological knowledge he needed to forecast where a storm would produce a tornado—or a row of them—and how powerful they were likely to be. From 1999-2001 he developed the HITPR, the first instrument package to survive a direct hit by a tornado core and record the central pressure and temperature profile. He called it "the turtle"; its shape was designed to hug the ground better and better as the wind grew stronger. Its first success came in 2003 in Manchester, SD.

Other successes followed, in spite that the funding he was able to attract was rather poor compared to some other "professional" groups. He continued to get measurements nobody else could get, right up until the end. This was in part due to his superior forecasting abilities, knowing which way a storm was likely to turn, so he could deploy one or more turtles (or successors thereof) and get out of there alive. In one case, the tornado core hit his device 15 seconds after he had turned it on!

His son Paul became a leading photographer and videographer for his work. Thus it was, that when his on-the-spot forecast was not spot-on, May 31, 2013, near El Reno, OK, he, his son, and a close friend, meteorologist Carl Young, were killed by an EF5 tornado. Its official wind speed, measured by others with radar near the time of his death, was 295 mph. The highest wind speed measured for the El Reno tornado was about 305 mph, the second tornado in history to exceed 300 mph. Here is where my estimates above are meaningful: if there is any meaning to the extrapolation I made, this was really an EF7 tornado, and by the older scale, nearly an F6. At the time Tim was killed, its "core" was 2.3 miles wide. The core is defined as the area within which wind speeds exceed 110 mph, at least for tornadoes EF2 and stronger. To people on the ground and comparatively nearby, who survived, it looked like an upside-down mountain, stuck in the Earth. To anyone closer than about a mile away from its outer edge, it seemed to fill from horizon to horizon, and hang overhead like a rippling cliff.

The following image, clipped from a YouTube video by Dan Robinson, shows the tornado from several miles away. Its visible funnel is "only" about a mile wide at this point, but the smaller funnel to the right is a suction vortex that shows the actual width of the whole storm. This vortex, if I read the book right, was itself moving around and around the core at around 100 mph, and had its own winds in the 150+ mph range. Thus the outer edge of that vortex—or one like it—would be the source of the extreme winds that approached and probably exceeded 300 mph.

Largely due to the work of self-educated engineer Tim Samaras, meteorologists and physicists are puzzling out the workings of these storms that produce most violent winds on Earth. RIP Tim Samaras and Paul Samaras and Carl Young. I am sorry you are gone. May your legacy continue. And much thanks to Brantley Hargrove for bringing their story to us, particularly folks who may never see a tornado for themselves.