TTAA00 KOUN 070120 PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE NORMAN OK 820 PM CDT THU MAY 6 1999 REPORT ON TORNADO DAMAGE IN GRADY AND MCCLAIN COUNTIES... A SURVEY TEAM COMPOSED OF METEOROLOGISTS FROM THE NATIONAL SEVERE STORMS LABORATORY AND THE NATIONAL WEATHER SERVICE HAVE COMPLETED INITIAL SURVEYS OF TORNADO DAMAGE FROM WEST OF CHICKASHA IN GRADY COUNTY NORTHEASTWARD TO NEWCASTLE IN MCCLAIN COUNTY. THIS REPORT INCLUDES DETAILS OF THAT PART OF THE DAMAGE TRACK ONLY UP TO THE SOUTH CANADIAN RIVER. INFORMATION ON THE DAMAGE SURVEY FOR LOCATIONS NORTHEAST OF THE SOUTH CANADIAN RIVER TO INTERSTATE 240 WERE CONTAINED WITHIN THE PUBLIC INFORMATION STATEMENT ISSUED YESTERDAY. INFORMATION ON THE DAMAGE SURVEY FOR OKLAHOMA COUNTY NORTH OF INTERSTATE 240 WERE ISSUED IN A PUBLIC INFORMATION STATEMENT EARLIER THIS EVENING. INFORMATION ON THE COMANCHE AND CADDO COUNTY TORNADOES FROM THIS SAME SUPERCELL STORM IS NOT INCLUDED IN THIS STATEMENT. FOUR TORNADOES OCCURRED IN GRADY AND MCCLAIN COUNTIES. ALL FOUR TORNADOES WERE ASSOCIATED WITH THE SAME MESOCYCLONE... INSTEAD OF A SERIES OF "CYCLING" MESOCYCLONES THAT METEOROLOGISTS SOMETIME OBSERVE WITH LONG-TRACK SUPERCELL THUNDERSTORMS. SOUTH OF VERDEN... THE FIRST TORNADO DEVELOPED FOUR MILES SOUTH OF VERDEN... AND QUICKLY INTENSIFIED TO A STRONG TORNADO WITH ASSOCIATED DAMAGE RATED AT THE HIGH END OF THE F3 SCALE. THE TORNADO TRACKED NORTHEAST ALONG A FOUR MILE PATH TO A POINT FIVE AND ONE HALF MILES DUE WEST OF DOWNTOWN CHICKASHA. MAXIMUM TORNADO WIDTH WAS ABOUT ONE-THIRD OF A MILE. THE TORNADO DESTROYED SEVERAL HOMES... INCLUDING ONE HOME WITH ONLY A FEW INTERIOR WALLS REMAINING. THE TORNADO ALSO DOWNED SEVERAL WOODEN HIGH TENSION POWER LINES. NORTHWEST OF CHICKASHA /TWO TORNADOES/... THE SECOND TORNADO DEVELOPED THREE MILES WEST-NORTHWEST OF DOWNTOWN CHICKASHA AND IMMEDIATELY CAUSED F3 DAMAGE TO A TWO-STORY BRICK HOME. THE TORNADO THEN CROSSED U.S. ROUTE 62 ON THE EXTREME NORTHWEST EDGE OF CHICKASHA CITY LIMITS AND MOVED NORTHEAST AND STRUCK THE CHICKASHA MUNICIPAL AIRPORT COMPLEX... RESULTING IN HIGH-END F2 DAMAGE TO TWO HANGAR BUILDINGS. A WING FROM AN AIRCRAFT AT THIS AIRPORT WAS EVENTUALLY CARRIED AIRBORNE AND DROPPED IN SOUTHWEST OKLAHOMA CITY. THE TORNADO CROSSED U.S. ROUTE 81 ABOUT TWO MILES NORTH OF ITS INTERSECTION WITH U.S. ROUTE 62... DESTROYING A LARGE BUILDING. THE TORNADO CONTINUED NORTHEAST AND DISSIPATED ABOUT 4 MILES NORTH- NORTHEAST OF DOWNTOWN CHICKASHA. THE PATH LENGTH WAS 6 MILES LONG AND MAXIMUM WIDTH WAS ABOUT ONE-HALF MILE WIDE. THIS TORNADO WAS ALSO ASSOCIATED WITH A THIRD BRIEF SATELLITE TORNADO THAT ROTATED AROUND THE SOUTH AND EAST SIDE OF THE MAIN VORTEX. DAMAGE FROM THIS SATELLITE TORNADO WAS NOT DISCOVERED... AND IS THEREFORE NOT RATED. NEAR AMBER THROUGH BRIDGE CREEK THROUGH NORTHWEST NEWCASTLE... THE FOURTH TORNADO WILL BE RECORDED AS AN F5 TORNADO - THE HIGHEST POSSIBLE RATING ON THE FUJITA SCALE OF TORNADO DAMAGE INTENSITY. TORNADOES ARE ASSIGNED A RATING BASED ON THE MAXIMUM DAMAGE INTENSITY OBSERVED... BUT ACTUAL DAMAGE OF THAT INTENSITY GENERALLY ONLY AFFECTS A VERY SMALL PERCENTAGE OF THE TOTAL DAMAGE AREA. F5 DAMAGE IN THIS CASE WAS VERY ISOLATED... BUT THE TORNADO LEFT A CONTINUOUS TRACK OF F4 DAMAGE FOR SIX AND ONE-HALF MILES IN GRADY COUNTY. THE TORNADO EVENTUALLY PRODUCED MORE AREAS OF F5 DAMAGE IN CLEVELAND COUNTY. THE TORNADO DEVELOPED ABOUT TWO MILES SOUTH-SOUTHWEST OF AMBER... CROSSED STATE HIGHWAY 92... AND QUICKLY GREW TO A VERY LARGE TORNADO AS IT PASSED EAST OF AMBER. THIS VIOLENT TORNADO MOVED NORTHEAST PARALLELING THE H.E. BAILEY TURNPIKE (INTERSTATE 44)... AND EVENTUALLY CROSSED THE SOUTH CANADIAN RIVER ONE MILE EAST OF THE TURNPIKE. THE SEGMENT OF THE PATH IN GRADY AND MCCLAIN COUNTIES WAS TWENTY-THREE MILES... AND THE TORNADO CONTINUED INTO NORTHERN CLEVELAND COUNTY AND EVENTUALLY OKLAHOMA COUNTY. THE TOTAL PATH LENGTH OF THIS TORNADO FROM AMBER TO MIDWEST CITY WAS APPROXIMATELY THIRTY-EIGHT MILES. JUST SOUTH AND EAST OF AMBER... THE TORNADO QUICKLY GREW TO CLOSE TO THREE-QUARTERS OF A MILE WIDE. ASPHALT PAVEMENT... ABOUT ONE INCH THICK... WAS PEELED FROM A SECTION OF RURAL ROAD /EW125 RD/ ABOUT FIVE MILES EAST OF STATE ROAD 92. THE FIRST DAMAGE RATED AT F4 WAS DISCOVERED ABOUT FOUR MILES EAST-NORTHEAST OF AMBER. F4 DAMAGE WAS OBSERVED CONTINUOUSLY FOR SIX AND ONE-HALF MILES... WITH ANOTHER AREA OF F4 DAMAGE ABOUT 2 MILES NORTHWEST OF NEWCASTLE. TWO AREAS OF F5 DAMAGE WERE OBSERVED. THE FIRST WAS IN THE WILLOW CREEK ESTATES... A RURAL SUBDIVISION OF MOBILE HOMES AND SOME CONCRETE SLAB HOMES IN BRIDGE CREEK. TWO HOMES WERE FOUND COMPLETELY SWEPT FROM THEIR SLABS... AND ABOUT ONE DOZEN AUTOMOBILES WERE CARRIED ABOUT ONE-QUARTER MILE. GRASS VEGETATION IN THIS AREA WAS COMPLETELY SCOURED TO MUD... AND SMALL CEDAR TREES WERE LEFT DE-BARKED AND DEVOID OF GREENERY. THE RIDGECREST BAPTIST CHURCH WAS DESTROYED NORTHEAST OF THE FIRST F5 DAMAGE AREA. THE SECOND F5 DAMAGE WAS ONE MILE WEST OF THE COUNTY LINE IN BRIDGE CREEK... AND CONSISTED OF A CLEANLY SWEPT SLAB HOME WITH FOUNDATION ANCHOR BOLTS AND ANOTHER VEHICLE LOFTED ONE-QUARTER MILE. THE MAXIMUM WIDTH OF THE TORNADO IN BRIDGE CREEK WAS ABOUT ONE-MILE WIDE. THE TORNADO MAINTAINED A NEARLY STRAIGHT PATH TO THE NORTHWEST OF THE TURNPIKE EXCEPT WHEN IT MADE A SLIGHT JOG TO THE RIGHT AND MOVED DIRECTLY OVER THE 16TH STREET TURNPIKE OVERPASS BEFORE RESUMING ITS ORIGINAL COURSE. THE TORNADO CONTINUED INTO THE NORTHERN SECTIONS OF RURAL NEWCASTLE... AND CROSSED THE TURNPIKE AGAIN JUST NORTH OF THE U.S. 62 NEWCASTLE INTERCHANGE. AT THIS LOCATION THE TORNADO NARROWED TO ABOUT ONE-QUARTER MILE WIDE AND THE DAMAGE INTENSITY DROPPED TO F2 BEFORE IT CROSSED THE SOUTH CANADIAN RIVER INTO NORTHERN CLEVELAND COUNTY. GREG STUMPF NATIONAL SEVERE STORMS LABORATORY JAMES LADUE NATIONAL WEATHER SERVICE/OSF DS NNNN