EF0 tornado, Sunset Hills, Virginia, April 27, 2011

1. EF065 to 85 mphthis tornado

   Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

2. EF186 to 110 mph

   Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

3. EF2111 to 135 mph

   Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

4. EF3136 to 165 mph

   Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

5. EF4166 to 200 mph

   Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

6. EF5over 200 mph

   Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

7. Unrated

   The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

Rating

EF0

Date

April 27, 2011

Touchdown

11:25 PM EDT (03:25 UTC)

Lifted

11:28 PM EDT (03:28 UTC)

On the ground

3 minutes

Path length

1.1 miles (1.8 km)

Path width

75 yards (69 m)

Deaths

0

Injuries

0

Property damage

$40,000

County

Fairfax County

Touchdown point

38.952, -77.345

Lift-off point

38.964, -77.331

Record number

1104272125-01

High pressure remained over the western Atlantic while a strong cold front slowly tracked through the Midwest. A southerly flow pumped in copious amounts of moisture from the Atlantic and Gulf of Mexico. The trough of low pressure associated with the cold front provided enough cold air aloft for moderate instability to develop. The instability combined with an upper-level disturbance rotating around the trough to trigger showers and thunderstorms. ||There was enough instability along with stronger winds aloft for some thunderstorms to become severe. Low level winds changed rapidly in speed and direction with height causing isolated tornadoes to develop.

The tornado began in a parking lot along Sunset Hills Road where small slimbs were snapped from a hardwood tree and a large limb was snapped from a softwood tree. The tornado crossed Sunset Hills Road and entered a golf course where it uprooted or snapped several hardwood and softwood trees. ||A few trees were snapped or uprooted along Wedge Road and a few homes appeared to have minor damage from the fallen trees. The tornado tracked toward the Oaks Village Center before weakening. Numerous trees were uprooted or snapped near the Oaks Village Center.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

The county was under a tornado watch, issued at 22:19 UTC and running to 04:42 UTC.

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The Storm Prediction Center had this point in a Slight Risk, with a 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 00:50 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Washington/Dulles (IAD), 10 km from the path, in the two hours either side.

From the Iowa Environmental Mesonet's archive of airport observations.

The Sterling radar (KLWX), 13 km away, was scanning. The volume nearest the touchdown began at 03:25 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

Local storm reports within 60 km of the path, in the three hours either side.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

The live radar over the trackEvery 2011 tornado in VirginiaEvery tornado in Virginia since 1950Warnings in force in Virginia nowThe forecast where you are

209 more were confirmed in the United States that day.

All 210 of them

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.