Public Information Statement
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
NOUS42 KKEY 121918
PNSKEY
FLZ076>078-131800-

Public Information Statement
National Weather Service Key West FL
315 PM EDT Sat Aug 12 2017

...NWS DAMAGE SURVEY FOR 08/11/2017 TORNADO EVENT...

.OVERVIEW...

On August 11, 2017 shortly after 5:00 PM EDT, damage to fish house
shed roof structures and boat coverings was observed in association
with a tornado near the working waterfront to the northwest of Safe
Harbor, Stock Island, Florida. Per examination of Doppler radar data
from KBYX (Boca Chica Key), the tornado may have initially developed
as part of a narrow landfalling waterspout or brief landspout
circulation.


.TORNADO...

RATING:                 EF-0
ESTIMATED PEAK WIND:    60-65 mph
PATH LENGTH /STATUTE/:  0.2 miles
PATH WIDTH /MAXIMUM/:   25 yards
FATALITIES:             0
INJURIES:               0

START DATE:             AUG 11 2017
START TIME:             5:03 PM EDT
START LOCATION:         3 ENE KEY WEST
START LAT/LON:          24.57/-81.73

END DATE:               AUG 11 2017
END TIME:               5:05 PM EDT
END LOCATION:           3 ENE KEY WEST
END_LAT/LON:            24.57/-81.74

SURVEY SUMMARY: The examination of a video of the event and
survey results revealed the first instance of damage to a hollow
metal tube roof structure topped with plastic or hard vinyl
covering, affixed to wood two-by-four supports of a fishing house
shed just northwest of Safe Harbor on Stock Island. The roof
structure was flipped airborne and deposited about 20 to 30 feet
to the west-northwest of the original location. The tornado
moved just south of due west, and lifted a boat tarp including
hollow tubing framework 30 to 40 feet into the air, depositing
it in a stand of Australian pines over 100 feet to the northwest.
A 15-by-15 foot folding tent structure topped with boat covering
structure was lifted airborne for several seconds and destroyed 20
to 30 feet from its original location. Another hollow tubing boat
covering frame, affixed via screws through flat plywood shims to
another fish house shack, and used as a shade overhang, was removed
as a single unit and deposited 20 feet to the east-northeast.  This
direction of damage deposition was nearly opposite the direction of
travel of the tornado. Numerous healthy small limbs of one half
(0.5) inch diameter of healthy Australian pine were desposited
toward the west-southeast across an unpaved dockfront access road.
Video examinination determined some of the limbs were severed as
the various roof covering structures struck the pine trees. It
was at this point that the maximum wind estimate of 60 to 65 mph
3-second gust was demonstrated.

The tornado then entered the harbor waters at an oblique angle,
causing a well-defined waterspout spray ring, and indicative of
3-second winds in well in excess of 50 mph.  The now-waterspout
crossed back over land as a tornado at the docks south of the 4th
Avenue curve on Stock Island, where loose objects aboard vessels was
lifted and deposited in a small turning basin. Eyewitnesses and
video indicated the tornado no longer lifted debris or spray at
that point, and seemingly dissipated.

Additional survey of adjacent properties and a large campground on
the Boca Chica Channel waterfront to the east of the area of impact
revealed no visual clues of tornado impact or landfalling waterspout.
Updates to this survey may be required if additional information
is obtained.

NOTE: The information in this statement is preliminary and subject
to change pending final review of the event and publication in NWS
storm data.

$$

JR



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.