Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >
A tornado outbreak occurred on Friday 17 September 2004 in the Mid-Atlantic states as Tropical Depression Ivan advanced northward up the spine of the Appalachians. Ivan had come ashore at about 3:00 am the previous day just west of Gulf Shores, Alabama as a powerful Category 3 Hurricane.
26 tornadoes touched down in the Baltimore-Washington Forecast Office Area of Responsibility. More than 100 warnings were issued by our office for counties and independent cities on Friday 17 September 2004 for tornadoes, severe thunderstorms, and flash flooding. |
The maximum intensity of these tornadoes ranged from F0 to F3 on the Fujita scale. Tornado intensity is ascertained by the amount and type of damage inflicted along the track of each tornado as surveyed by National Weather Service Meteorologists. |
F0 | F1 | F2 | F3 | F4 | F5 | |
# During Outbreak | 5 | 12 | 8 | 1 | 0 | 0 |
Estimated Wind Speed | 40-72 mph | 73-112 mph | 113-157 mph | 158-206 mph | 207-260 mph | 261-318 mph |
Damage Description | Some damage to chimneys and TV antennae; breaks twigs off trees, pushes over shallow-rooted trees | Peels surfaces off roofs; windows broken; light trailer houses pushed over or overturned; some trees uprooted or snapped; moving automobiles pushed off road | Roofs torn off frame houses leaving strong upright walls; weak buildings in rural areas demolished; trailer houses destroyed; large trees snapped or uprooted; railroad boxcars pushed over; light object missles generated; cars blown off highway | Roofs and some walls torn off frame houses; some rural buildings completely demolished; trains overturned; steel-framed hangar-warehouse type structures torn; cars lifted off the ground; most trees in a forest uprooted, snapped, or leveled | Whole frame houses leveled, leaving piles of debris; steel structures badly damaged; trees debarked by small flying debris; cars and trains thrown some distance or rolled considerable distances; large missiles generated | Whole frame houses tossed off foundations; steel-reinforced concrete structures badly damaged; automobile-sized missiles generated |
...WASHINGTON COUNTY MARYLAND... A THUNDERSTORM PRODUCING A TORNADO MOVED NORTH OUT OF NORTHERN LOUDOUN AND SOUTHWEST FREDERICK COUNTIES INTO EASTERN WASHINGTON COUNTY. IN BOONSBORO 5 HOMES WERE DAMAGED DUE TO TREES FALLING INTO THEM. PART OF A ROOF WAS DAMAGED AS A RESULT OF THE TORNADIC WINDS. THIS TORNADO WAS ESTIMATED TO BE AN F0 ON THE FUJITA SCALE WITH WINDS ESTIMATED AT 60 TO 70 MPH. THE PATH WAS 1 MILE LONG WITH A WIDTH OF 75 YARDS. A TORNADO BRIEFLY TOUCHED DOWN IN WESTERN WASHINGTON COUNTY EAST OF HANCOCK LATER FRIDAY EVENING. THIS TORNADO DOWNED TREES IN REMOTE AREAS AS CONFIRMED BY GROUND SURVEY. THE TORNADO WILL BE RATED AN F0 ON THE FUJITA SCALE. THE PATH LENGTH IS ESTIMATED TO BE 1/2 MILE IN LENGTH WITH A WIDTH OF 100 YARDS. |
...CHARLES COUNTY MARYLAND... A TORNADO RATED F0 TOUCHED DOWN IN SOUTHWEST CHARLES COUNTY MARYLAND AROUND 640 PM. THIS TORNADO WAS SPAWNED BY THE SAME THUNDERSTORM THAT EARLIER HAD PRODUCED A TORNADO IN KING GEORGE COUNTY, DESCRIBED ABOVE. AFTER CROSSING THE POTOMAC RIVER THE TORNADO MADE LAND FALL ON THE CHARLES COUNTY SHORE NEAR MARYLAND POINT. THERE IT DOWNED NUMEROUS TREES NEAR THE MERRICK 4-H CAMPGROUND. AFTER IT CROSSED NORTH OF RIVERSIDE ROAD, THE TORNADO DOWNED AND TOPPED TREES ALONG WILLIAMS FARM PLACE AND AMERICAN BEAUTY PLACE. THE TORNADO DISSIPATED SHORTLY AFTER DOWNING TREES NEAR THE INTERSECTION OF MARYLAND POINT AND SMITH POINT ROADS. PATH WIDTH WAS ROUGHLY 100 YARDS WIDE. TOTAL PATH LENGTH WAS 3 MILES. |
...MORGAN COUNTY WEST VIRGINIA... A BRIEF TORNADO TOUCHED DOWN IN THE SLEEPY CREEK AREA OF NORTHEAST MORGAN COUNTY. TREES WERE DOWNED AND A TREE FELL ON A RESIDENCE. THE DAMAGE SURVEYED IN THIS AREA WAS ALSO CONSISTENT WITH WEAK TORNADO DAMAGE. THE TORNADO WAS AN F0 ON THE FUJITA SCALE AND WAS ON THE GROUND FOR APPROXIMATELY ONE HALF MILE. THE MAXIMUM WIDTH OF THE TORNADO WAS AROUND 100 YARDS. |
...HARFORD COUNTY MARYLAND... TWO SEPARATE TORNADOES ASSOCIATED WITH THE REMNANTS OF IVAN STRUCK HARFORD COUNTY DURING THE PRE-DAWN HOURS ON SATURDAY SEPTEMBER 18TH. THE FIRST HIT NEAR PYLESVILLE OR IN THE NORTHWEST PART OF THE COUNTY AND WAS RATED F2. THE SECOND WAS A BRIEF TOUCHDOWN NEAR JOPPA IN THE SOUTHEAST PORTION OF THE COUNTY. THE SECOND TORNADO WAS RATED F1 AND WAS EMBEDDED IN A LARGER AREA OF DAMAGE ATTRIBUTED TO STRONG THUNDERSTORM STRAIGHT LINE WINDS. PYLESVILLE TORNADO, DAMAGE BEGAN NEAR A RESIDENCE OFF GRIER NURSERY ROAD SOUTH OF PYLESVILLE ROAD (MD 165). MANY LARGE PINE TREES UP TO 3 FEET IN DIAMETER WERE UPROOTED OR SNAPPED. SLATES WERE PULLED OFF THE ROOF. DAMAGE HERE WAS RATED F1. FURTHER NORTH ON MD 165 THE TORNADO DAMAGED A HOME AND OUT BUILDING BOTH UNDER CONSTRUCTION. IT BLEW OUT THE SIDE OF A BARN JUST NORTH OF THIS HOME. MORE F0 TREE DAMAGE WAS NOTED ALONG ST MARYS ROAD. AS IT MOVED NORTH THE TORNADO DESTROYED A MOBILE HOME LOCATED OFF WHEELER SCHOOL ROAD. A 1X3 PIECE OF LUMBER WAS HURLED INTO THE SIDE OF A STORAGE SHED. FURTHER UP ON WHEELER SCHOOL ROAD IT DEMOLISHED A STORAGE BUILDING AND DID DAMAGE TO THE PATIO AND BACK ROOM OF A RESIDENCE AND TOOK OUT A LARGE NUMBER OF TREES INCLUDING HARDWOODS. THE TORNADO WAS RATED LOW END F2 AT THIS TIME. FURTHER DAMAGE WAS NOTED ALONG WHITEFORD ROAD (MD 136) IN THE VICINITY OF THE FIORE WINERY. LARGE HARDWOOD TREES WERE UPROOTED OR SNAPPED OFF. A TRAILER THAT WAS TIED DOWN WAS COMPLETELY DEMOLISHED WITH 4 PEOPLE INSIDE. NEARBY THERE WAS ROOF DAMAGE TO ANOTHER HOME AND PORTIONS OF AN ABOVE GROUND POOL WERE CRUSHED. THIS AREA IS ON A RIDGE TOP. THE TORNADO WAS RATED LOW END F2 AT THIS TIME. THE LAST AREA OF DAMAGE IN THIS PART OF THE COUNTY WAS MAINLY TO TREES SURROUNDING A HOME ALONG ARCHER ROAD LESS THAN 1/4 MILE FROM THE PA BORDER. THE ROOF OF A STORAGE BUILDING WAS ALSO BLOWN OFF HERE. TORNADO WIDTH VARIED FROM 50 TO 125 YARDS. PATH LENGTH WAS 2 MILES. JOPPA STORM, INITIAL DAMAGE FOUND IN THE GREENSPRING HILLS SUBDIVISION SOUTH OF MOUNTAIN ROAD (MD 152) WAS DUE TO STRONG STRAIGHT LINE WINDS. MANY TREES WERE UPROOTED AND A TRAVEL TRAILER WAS OVERTURNED, WITH WINDS ESTIMATED BETWEEN 80 AND 90 MPH. AS THE STORM EXITED THE SUBDIVISION, THERE WAS STRONG EVIDENCE OF A TORNADO. IN THE 1900 BLOCK OF MOUNTAIN ROAD TREES WERE FELLED AND A SINGLE STORY HOUSE SUFFERED EXTENSIVE ROOF DAMAGE. WINDOWS WERE BLOWN OUT AT THE HOUSE NEXT DOOR. THE TORNADO KNOCKED DOWN OR TOPPED TREES ADJACENT TO THE MOUNTAIN BRANCH GOLF COURSE CAUSING F0 DAMAGE. A HOME ON STOCKTON ROAD SUFFERED DAMAGE DUE TO TREES FALLING AROUND IT. THE TORNADO CONTINUED NORTH FOR A SHORT DISTANCE WHERE IT PEELED SOME SIDING OFF A FEW HOMES AND BLEW DOWN MORE TREES BEFORE IT LIFTED. THE TORNADO PATH LENGTH WAS ABOUT 1 MILE LONG WITH A MAX WIDTH OF 100 YARDS. |
...IN SUMMARY... THE PRELIMINARY INFORMATION PROVIDED ABOVE IS STILL IN THE EARLY STAGES OF COMPLETION. THE FINAL OFFICIAL INFORMATION WILL BE CONTAINED IN NOAA'S STORM DATA PUBLICATION. THE NATIONAL WEATHER SERVICE EXTENDS ITS GRATITUDE TO THE LOCAL MEDIA, EMERGENCY SERVICES AND LAW ENFORCEMENT OFFICIALS AND SKYWARN SPOTTERS FOR THEIR ASSISTANCE BOTH DURING, AND NOW AFTER THIS EXTREME WEATHER EVENT. |
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