tornadoes, lightning bugs, and other summer wonders.
By Fred Schaaf
Many people think of spring as the season for tornadoes,
and generally they are right. The strongest tornadoes
usually reach their peak of occurrence in May. About the
third week of May, Oklahoma and the Texas Panhandle is, on
an average, the place and time where the world's most
violent weather phenomenon is at its fiercest and most
common. Back in February, we saw — tragically —
that Florida and the Gulf Coast have an early tornado
season, though usually not as early as in this year of a
strong El Niño. Likewise, June and July bring the
threat of tornadoes farther north — to eastern
Colorado, for instance, where smaller tornadoes are
numerous in early June, and even to the Northeast U.S.,
where a second peak of frequency for the year comes in July
and early August.
Most of us have heard that tornadoes in the Northeast are
usually far less powerful than their cousins in the Plains.
But what's interesting is that scientists and storm-chasers
have learned so much about severe weather in the past few
decades that they can now give separate terms to a number
of different varieties of atmospheric vortex, including
some of the weaker tornadoes. This isn't just a matter of
classifying tornadoes from FO (weakest) to F5 (strongest)
on the famous Fujita scale, which relies on the type of
damage caused. Different tornadoes and other whirlwinds
have different means of formation.
Two kinds of vortex which are visibly different than
tornadoes have been known and named for a long time:
waterspouts and dust devils. You might think that a
waterspout is just a tornado over water. Actually, the true
waterspout forms over the water and is typically much
weaker than a tornado. In cases where the vortex forms from
a severe thunderstorm over land and moves onward to pass
over water, it can have a ferocity far exceeding the true
waterspout. As for dust devils, these whirls occasionally
can be big and strong enough to be dangerous, but their
genesis is from localized heating. Their source of energy
is limited. The source of most strong tornadoes is the
energy of a major weather system concentrated by a
super-cell thunders, form and a special rotating region of
these storms called a mesocyclone. The mesocyclone. might
be typically five miles in diameter and produce a tornado
up to a mile wide.
Lightning Safety Remainders
Lightning kills more people in the U.S. each year than
tornadoes do. Many of the deaths and injuries could have
been avoided if people followed certain basic safety tips.
I've discussed some of these here before, but it's well to
When is lightning too close for you to be outside? You can
estimate the distance of lightning by noting the number of
seconds between the lightning and its thunder and dividing
this by five to get the distance in miles. Certainly
lightning three miles away is getting too close for safety.
In fact, you should really play it much safer, because
there i no guarantee that the next bolt will not come from
another part of the cloud and be tight on you. If far from
shelter initially, remember that thunderstorms can
occasionally advance at speeds of 50 mph or faster.
The worst situation of all is to be the highest object in
an area. A boat or swimmer on the water or a person
standing in a large field or out on the open plains is in
grave danger of being struck by lightning. If you can't
escape and find yourself in this situation, get down as low
as possible—even if you feel your lair stand on end,
you may avert the strike if you throw yourself down. Water
is worst of all because it can conduct electricity so well.
Most people realize that they are relatively safe from
lightning in a motor vehicle, with its goal grounding and
rubber tires. On the other hand, most don't realize how
hazardous—potentially deadly-it is to be on the phone
with an electrical storm nearby.
Waterspouts and dust devils look very different and occur
in very different environments than tornadoes. But some of
the new subclasses of tornado would not immediately he
differentiated by the layperson, Some of these terns for
them are slang of storm chasers, but they make gold sense.
A landspout is a small weak tornado which typically doesn't
arise from a mesocyclone or a supercell but instead from
less severe thunderstorms and other convective clouds. Most
of the many tornadoes of eastern Colorado in June are
landspouts. A gustnado is a weak tornado which is formed
from the gust front, the line of winds which races out
ahead of a thunderstorm.
A LM A NAC June-July 1998
2 Coronation Day (in U.K.). 3 First American spacewalk, by
Edward White on Gemini 4 in 1965.
6 World Environment Day.
7 Trinity Sunday.
10 FULL MOON, 12:18 A.M. EDT; Mercury at superior corn
junction with Sun and unviewable (see later this month);
date on which Ben Franklin is reputed to have performed his
kite in a lightning storm experiment
11 Corpus Christi; King Kamehameha I Day (Hawaii).
14 Earliest sunrise (5:30 A.M. daylight saving time) for
40' North latitude.
16 First woman—Valentina Tereshkova—launched
into space on Vostok 6 in 1963.
17 Bunker Hill Day (Boston and Suffolk Co., Mass.); Moon to
lower right of Jupiter before dawn.
18 First U.S. woman launched into space—Sally
Ride—on Challenger this day 15 years ago.
19 Moon to right of Saturn before dawn.
20 West Virginia Day.
21 Father's Day; Summer solstice, 10:03 A.M.
EDT—summer begins in Northern Hemisphere of
22 Pluto's moon Charon (pronounced KAIR-on) discovered this
day 20 years ago by U.S. Naval Observatory astronomer James
24 Midsummer's Day; St. John's (the Baptist's) Day.
25 Mercury visible low in west-northwest about 45 minutes
after sunset, about one width of your fist held out at
arm's length to the left of a very thin crescent
27 Latest sunset (8:33 P.M. daylight saving time) for
40° North latitude.
28 Mercury makes line with stars Pollux and Castor (to
right of Mercury), low in west-northwest about 45 minutes
30 Ninetieth anniversary of the Tunguska Event, mysterious
explosion over Siberia.
1 FIRST QUARTER MOON, 2:43 P.m. EDT (rust instance of this
phase this month); Canada Day.
2 Midpoint of the year at 1 P.m. local time if you are on
daylight saving time (noon, If you are on standard
4 independence Day—this year, 222nd anniversary of
signing of the Declaration of Independence; this day in
1956, Unionville, Maryland received 1.23 inches of
rain—in 1 minutes!
5 Brilliant Venus to left of V-shaped Hyades star cluster
(face of Taurus the Bull) before dawn.
6 A foot and a half of snow fell on the summit of Pikes
Peak on July 6-7 in 1883.
8 Mercury at highest in west-northwest during dusk (look
for it about 45 minutes after sunset) for anywhere near
40° North latitude; Venus extremely near a star in
Taurus before dawn (telescope needed).
9 FULL MOON, 12:01 P.M. EDT.
10 Temperature hit 134°F, an all-time record for the
Western Hemisphere, in Death Valley, California this day in
1913; Martinsburg, West Virginia had high of 112°F
(tied for highest ever in U.S. east of Appalachians) on
this day in 1936.
11 Pieces of the Skylab space station survived re-entry to
crash in the Indian Ocean and Australia in 1979.
12 On this one day in 1940, lightning started 538 fires in
the northern Rockies.
13 Barrow, Alaska — the northernmost town in the U.S.
— hit an all-time record high of 79°F in
14 Spring comes to life in the Northern Hemisphere —
15 Moon lower left of Jupiter before dawn; Venus near the
star Zeta Tauri (use binoculars) before dawn.
16 LAST QUARTER MOON, 11:13 A.M. EDT; first atom bomb
explosion took place this day in 1945.
17 Moon below Saturn before dawn; Mercury at greatest
evening elongation from Sun (28°).
18 Jupiter reaches stationary point then begins retrograde
motion (westward relative to background stars).
20 Sun enters the constellation Cancer, 6 P.M. EDT.
21 Moon well to right of bright Venus and dim Mars before
dawn; Venus near star cluster M35 in Gemini (use binoculars
23 NEW MOON, 9:44 A.M. EDT; Neptune at opposition —
biggest and brightest of year, but you'll still need a
telescope and finder chart.
24 Pioneer Day (Utah); in 1959, temperature hit a low of
89°F in Yuma, Arizona.
25 In 1956, the passenger liners Andrea Doria and Stockholm
collided in fog off Nantucket; the former sank 12 hours
later, killing 51.
28 Delta Aquarid meteor shower at its peak around now
— look for these "shooting stars" from out of the
south in the hours following midnight. Some will still be
visible as late as two weeks from now.
29 Venus and Mars pull closer together in the dawn sky as
the month ends.
31 The lunar rover carried Apollo 15°s Scott and Irwin
completely around the lunar surface in 1971.
A cold-air funnel is another generally weak tornado or
funnel cloud, which has yet another means of production
— relatively cool, comparatively stable conditions.
The only major vortices I've ever seen were a group of
cold-air funnels in North Dakota. A meteorologist friend
and I rode bicycles to within about a mile of the nearest
of these funnels before it dissipated. We weren't taking
much of a risk, though in rare cases such a vortex might
generate winds in roughly the 70 to 100 mph range.
By the way, a funnel cloud is a condensation funnel which
is not in contact with the ground. If its end ever touches
the ground, it is then classified as a tornado. Not every
tornado has a visible funnel, however. In some cases, an
observer may see only a whirl of debris down on the
surface, but the phenomenon can still be classified as a
tornado. It can still be pan of a violent storm, however,
and nay or tray not he something fun to chase after on your
The sky can bring many other wondrous of summer's arrival.
One of the most welcome a that first early June night when
the fireflies begin their flashing.
There are other luminescent creatures in the world, but
none quite like these. There are about 50 species in the
U.S. and many more in the tropics. All share the property
of having a marvelous final segment or two of their soft
bodies which is capable of lighting up with a pale
What is the secret of this cool green illumination? How do
fireflies produce light without heat? Scientists have
identified the chemicals luciferin, luciferase, and
adenosine triphosphate at work, and there apparently has
been progress in understanding the cold fire in recent
years. But much of the mystery remains. We see it on the
wing, the living lights of the fireflies putting out their
marvelous messages in light to attract mates.
Glowworms are the wingless females of some firefly species.
They signal to the airborne males above from among the
stems of grass. Fireflies are not flies, but a kind of
The larvae live underground and in rotting wood or refuse.
They eat tiny insects, as the adults probably do too
— except for some kinds which may never eat at all
once they become adults.
Early summer seems to be the optimum time for fireflies. In
his book A Walk Through the Year , naturalist and
entomologist Edwin Way Teale writes of a great display of
fireflies observed by him and his wife in Connecticut on
one June 21.
Teale goes on to say that fireflies seem most numerous in
the air between about 10 P.m. and midnight, "on nights
moist and warn." It seems many of us—Teale and I
included — have looked up spellbound to see them
intermingle with numerous stars in what were, therefore,
rather non-humid nights. Is that point of light you see 60
feet or 60 light-years away? I'm pretty certain I've seen
fireflies floating among the tops of 100-foot tall tees,
but their distance can indeed be difficult to estimate.
I wonder if it was heat, humidity, or both which has set
off displays of fast, seemingly wild and erratic flashing
which I've seen in fireflies a few times when a
thunderstorm was approaching. Could their strange behavior
have been due to the charge in the air? From the ozone from
lightning? But the storms had not arrived yet...
Or — is it possible? — were the little bugs
reacting to the flashing from what their instincts mistook
for a sky-wide firefly? Some people — my wife is one
of them—grew up calling fireflies by one of their
popular names: lightning bugs.
Surely everyone has caught a firefly in his or her hand and
watched the pulsing glow shine out from within. We still
often hear people encouraging kids to capture—and
keep — as many of them as possible in jars. That may
not be such a good idea. Of course, in some years and some
places, the number of fireflies is stupendously
large—in the year of Teale's memorable display he
asked, "In this June night, who can guess how many billion
fireflies are on wing above the dark fields of eastern
But there are individual species of firefly whose
numbers are small. In any case, we creed to teach respect
for the living world to our children. If, as a child, you
don't learn respect for the magic of fireflies, what in
nature will you ever respect?