Re: Backpacking and Tornadoes
Bob Amick (amick@spot.colorado.edu)
Fri Jun 05 14:32:00 1998
Bill, et al
You may want to look at the American Red Cross disaster web page
for some good references on tornadoes. They have links to the
National Weather Service/NOAA, FEMA, and the Weather Channel as well.
http://www.redcross.org/disaster/safety/tornadoes.html
Tornadoes in the wilderness are a less commonly addressed topic,
so there is probably not as much information on response and preparedness
than their would be for an urban setting.
However, the synopisis of advice for a wilderness response to
a tornado threat would be to find an open area and lie down flat,
in a depression or ditch if possible, away from trees and other
potential hazards; cover your head with clothing or a backpack
for protection from flying debris. A cave or rock overhang might be a better
option if you could find one, but chances are they wouldn't be
readily available when you needed them. In more urban settings,
seeking shelter under a highway bridge or overpass, or even a
large culvert would be advisable. Folks in cars should stop them, get out
and run immediately to a sheltered area or as noted above, lie down
flat in an open area.
If buildings can be found, going to the basement is best, otherwise inner
walls/hallways of the main floor
and away from doors and windows to avoid flying glass and debris
is preferable. Contrary to popular opinion, opening or closing
windows/doors has no effect on safety and only wastes time that should
be spent finding immediate shelter. The worst thing that most folks
do is stand out in harm's way and "gawk" at the approaching funnel
cloud when they should be finding shelter as quickly as possible.
Many have died due to this behavior. This is due to a "denial"
perception that such storms and weather phenomenon "cannot possibly
be a threat to me.." Often when folks realize that they are imminently
in harms way, they are too late to do anything about it.
Note the precaution that lying flat in a ditch or depression during
a tornado can also subject you to flash flood hazards related to the storm,
as well as to risk of lightning strike, so it is advisable to get to
a safer location once the tornado has dissipated or left the area.
Probably the most important skill is recognition of the potential
for a tornado forming. Checking weather forecasts before you go,
and watching for the formation of "wall or anvil clouds" and clouds with
a dark greenish tinge, as well as those which form "nipples" which
often are the precursor of funnel clouds may give you enough time
to alter your route and get to a safe area. Another imminent warning
is of course the "roaring sound" caused by the winds which some
compare to a "railroad train engine noise." NOAA weather radio
constantly broadcasts weather warnings, and small, battery operated
weather warning radios are available inexpensively at local electronics
stores such as Radio Shack. Early tornado watches are often given when
there is a potential for a storm which can form tornadoes so you may
have plenty of time to take precautions and move to another more
safe area.
The good news is that tornadoes in mountainous country are seldom as severe
as those on open or plains area since mountains tend to inhibit the formation
of large powerful funnel clouds. However, even an F1 tornado can certainly
due substantial property damage and cause personal injury.
Most mountainous tornadoes are seldom
larger than F1 or F2, whereas plains tornadoes can reach up to F5 which is
devastatingly dangerous to life and property.
An associated hazard which is equally dangerous is of course lightning.
The preferred response for imminent lightning strikes in open or
exposed areas such as ridges on mountains is now to
crouch into a "squatting" position with your feet together and your
arms around your knees or alternatively, your hands covering your
ears to protect from the sound impact of lightning.) Only your
feet should be touching the ground to avoid transfer of electrical
energy from the "ground wave" of a lightning strike that may stop
the heart or cause ventricular fibrillation. Being inside buildings
or in cars is the safest option since the structures or vehicles made
of metal act as "faraday cages" and conduct energy around the occupants to
ground.
The tires on the vehicle have no "insulating value" as is commonly thought.
Lightning strikes can occur on seemingly "clear days" where a cloud formation
is several miles away, however a bolt can travel many miles and contains
hundreds of millions of volts of electrical energy and very high amperage.
The average lightning bolt is only about 1 inch in diameter, but appears
much larger due to the brilliant light emitted. It has a temperature which
is about five times hotter than the surface of the sun. Many tragic strikes on
golf courses, parks, and open playing fields have happened during seemingly
sunny clear days, so when storms threaten, take precautions even if the storm
is miles away; get folks inside buildings, into cars, and off the water,
promptly.
Remember that most lightning strike victims survive, but may need
immediate CPR and advanced life support from paramedics (defibrillation
and cardiac drugs). Only those who are directly hit by a strike such
as might occur by being close to
a tree or out on a body of water are more likely to be fatally injured.
Bob Amick, EMT-B, Explorer Advisor, High Adventure Explorer Post 72/SES 72,
Boulder, CO
Longs Peak Council Exploring Training Chair; American Red Cross Community
Disaster
Education Instructor/Advisor, Emergency Management Explorer Post 493
At 02:07 PM 6/4/98 -0400, you wrote:
>To all our backcountry experts,
>
let's just say that you're deep in the forest when
>something like this occurs. There's hail, 60+ mph winds, driving rain,
>etc. and you're surrounded by trees (any of which might decide to
>topple). And then there's the possibility of the funnel cloud itself
>coming along, which you can't see because of the forest canopy.
>
| 
