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