STORM TRACK: November 30, 1983 (Volume 7 Issue 1)

One of ST's Iowa subscribers, Douglas M. Beadle, wrote: "I wanted to suggest the possibility of including storm chasing safety tips in a future issue of ST." The Editor thought this a good idea, especially for new, recent readers who have had little experience along this line. ST's response follows each of Doug's topical categories, along with some additional tips. These comments will, necessarily, be abbreviated, since a full response could easily fill a small book. If readers have additional suggestions or take issue with any of the following, let me know in time for the spring issues of ST.

(1) "Safe distances and directions from storms under various circumstances." "Safe" is a dubious condition under or even a few miles from the anvil of a severe thunderstorm.

(a) Lightning - Cloud to ground lightning can occur anywhere in this area, arcing out several miles from a storm to strike the ground under an otherwise clear sky. therefore, "safe" is in your car where an uninvited charge can pass around and to the ground. When driving through intense lightning, I avoid contact with metal trim, to the extent possible. When stopping for pictures, I usually locate within 1/2 mile of a higher object like a tree or windmill. If I must leave the car, move quickly away from it and assume a crouch position for a few quick pictures. If you feel your hair standing on end, when outside, drop immediately to your haunches (Fig. 1). You may avoid becoming theconductor for the charge that is building up around you. For additional lightning information, see ST. Vol. 1, No. 3.

Figure 1

(b) Location - The safest approach/location, other than for lightning considerations, is SE-SW of the southwest flank of the storm, but can be as close as a few miles from the edge of the rain shield. Be alert, however, to storms moving from the NW. Then, your best location is near the west flank. As you approach any storm, try to visualize in your mind's eye a standard NE moving severe storm cell from above (Fig. 2).

Figure 2. Schematic from several papers by C. Doswell and L. Lemon.

Based on the last radio radar report, you know the storm's movement (be sure to differentiate reports for "cell" versus "line" movement -- a squall line can move easterly, while individual cells move northeasterly within it). Then visualize the trailing flank, where new convection is taking place. Move to that location; or to the southern-most storm cell in a line and then to that, location. Note also any reports on the storm's forward speed. Stop and plot your estimated intersect point. Take a minute or two to plan this carefully via the best roads and estimate time of arrival. There's no point in trying to catch a tornadic storm 50 miles east of you, if it's moving NE at 40 MPH. After an hour of hard driving on the typical east-west highway, it, will still be 35 miles NE, and you've still got to go twice as far again east before turning north for an intersect -- add another two hours minimum. Of course, by that time the original storm is almost three hours old and if you haven't lost your daylight for photography it has probably long since dropped its tornado. Moreover, you've wasted gas, overheated the engine and probably have a ticket to boot. It's not worth it! There's no percentage in driving fast or recklessly -- be patient, and plan for the long haul. Don't be tempted to drive "all out" to catch just one storm, even the last one of your vacation, when you may kill someone or even yourself. You'd be surprised at how many "sure fire" storms of beautiful structure and size never drop anything more than hail.

(c) Floods - This anticipates a later question from Mr. Beadle but is appropriate to mention here in response to his initial focus area. Chasers need to be continually alert to the danger of flash flooding, even several miles from a severe storm. The plains are deceptively flat, and any slight lowering in the terrain can rapidly fill with runoff. This is an especially serious concern for those of you driving unfamiliar roads or at night. You won't know until too late if that watery film you're about to race through to the other side of the road is actually four feet deeps I've done it and was nearly swept off the road on the north side of Tulsa. It takes only one good hard scare like that to learn a lifetime lesson.

Figure 3

I also remember one particular stretch of back road in the Texas panhandle the day after a tornadic storm with flash floods. I drove into a typical little panhandle valley (maybe 80-100 ft down), across a mud streaked road with caution flags on both shoulders and was looking up at matted tufts of prairie grass along the high-water line, well above the car top (Fig. 3). It was mostly dry this day after, with just a little muddy stream flowing nervously through the concrete culvert, under the road that -somehow- remained. I tried but couldn't imagine the torrent of the night before, so out of place now under the blue, tranquil skies overhead. On another storm afternoon, the radio urgently reported cars being swept off a road between Hereford and Amarillo -- a road I had just traveled only hours before but couldn't (for the life of me) remsmber any low place, in all that flat expanse, sufficient for that kind of hazard. The point is -- be watchful for surprises and listen to the radio. Remember when a situation like this gets out of hand, it is already out of hand.

In the same context, if caught in rising water (engine floods out) and you don't want to be swept off the road into a more turbulent water course, try opening the door and let the water in! A modern car with closed doors, rising water and a swift current will eventually float (Fig. 4). It may then be swept from the higher road surface to a worse fate, catching against an underwater obstruction and overturning into much deeper water. Try opening the door on the side farthest from the current to admit water and reduce buoyancy (this is strictly my own recommendation; others may disagree -- what do you think?)

Figure 4

When driving on wet pavement and you can do so safely, straddle the wet streaks that identify the tire worn depressions on the road surface. This avoids hydroplaning, and you can maintain speed.

Another rain related caution: check those tires before setting out! Poor tread is poor traction! Either buy new tires or adjust your driving accordingly, especially on wet curves. Item - Three chasers were returning down I-40 in western Oklahoma one night, after a chase and at normal speed, with semi-bald tires on wet pavement. The car suddenly began to slide and then did three complete doughnuts before coming to rest across the center-line of the eastbound lane. No other cars were involved. The dozing chaser on the back seat sat, up fast and said, "Hey! We weren't going straight were we?" The rattled driver shot back, "Shut up, Eddie! Go back to sleep!" Refusing to continue, the shaken driver changed places with his equally ashen seat mate, who took the wheel and eased it on home (account from R. Zipser). The lesson: know the limits of your car and don't push it! Be constantly alert; the risk is greatest when you're most tired.

Finally, watch out for soft shoulders on back roads. I've traveled many of these at posted speeds (usually 55 MPH) and nervously eyed the wet earth just inches from my tires, With just a moment's inattention, your right-front tire can drift off, dig instantly into the rain-softened shoulder, and spin/flip the car (Fig. 5). Think safety!

Figure 5

(2) "Dangerous areas of the storm to be near, i.e. hail damage, lightning strikes, heavy rain ..."

(a) The Wall Cloud - Any area underneath a wall cloud is dangerous. A wall cloud is a lowering underneath cloud base on the south or southwest flank of a storm, usually just outside the rain shield (Fig. 6). A wall cloud can form in 10-20 minutes and a tornado can occur under or near it (frequently just west of it) at any time thereafter. However, a wall cloud is not always clearly evident, or even essential, especially for high-based, storms (5,000' or more). If the latter produces a tornado, it will tend to be of the small rope nature, but from the same area of the storm (southwest flank of a NE moving cell).

Figure 6

Conversely, a lower storm base with a large wall can produce multiple vortices beneath it. The area beneath a wall usually affords good visibility, since this locates the dominant updraft and usually has very little rain. If you see some light precip underneath, study the rain curtain. It will often give you the first indication of developing rotation; watch for rain streamers moving in opposite directions. If you're on the inside looking out, of course, get out fast -- to the south.

Another caution, look out for low, ground dust swirls beneath the southwest flabby of a storm. They may look like the dust devils that spin up frequently on a hot day, near or along the shadow/sun boundary of a cloud. However, if completely within the shade of a storm, they could be the surface extension of an invisible tornadic rotation, extending all the way to cloud base. They are more common in the western states, where relatively drier airinhibits formation of a condensation vortex. Watch out for these and don't drive through them.

(b) Hail - Avoid the heaviest precip area N-NE of the clear updraft region unde the southwest flank, especially within two to four miles of the wall cloud (Fig. 2). If you can't see this part of the storm and are approaching from the north or northeast, avoid any heavy precip areas that you encounter. It is generally alright to pass under the anvil, if you can still see the horizon. Remember that the anvil may extend 50-100 miles easterly of the turbulent, hail rich base, which is only about five to ten miles in diameter at the southwestern end. You may encounter some anvil hail, being carried by high level winds from the updrafting towers west of you. However, these stones are normally small and, other than making a great clatter on your roof, won't break any glass. Based on the last radar report for cell movement, try to intersect the anvil at right angles to its track. Most anvils are football shaped, so a perpendicular transit will cut across its narrow portion. Keep Fig. 2 in mind regarding its overall structure. If the hail/ rain curtain under the anvil overtakes you, continue on your course. Remember that the hail shaft has to move with the storm. Better to continue driving through the initially light hailfall than to stop and wait it out. The stones will only become larger as the storm's core approaches. Your car windows will generally resist hail up to two inches, depending on your speed and their angle of fall.

One suggestion, use your windshield wipers sparingly in hail. I drive slowly, with lights and use about one swipe every 3-4 seconds. Slanting blows on the wipers can damage the gear unit and ground you for repairs. When visibility can be maintained, reducing their use minimizes the possibility of hail damage.

(c) Wind - A final reminder when opening the car door in high wind. Grip the handle or arm rest securely before exiting. If you stop with your tail to the wind and, absorbed what you're looking at, forget its direction, you can push the door open and the wind will very nearly take it off its hinges. A sprung door would be a costly lesson, especially if you got nothing else to show for that day but a stiff repair bill. Think! Storm chasing is no casual vacation. It requires planning, patience and attention to detail.