Tornadoes · United States · Maryland · 2011

EF0 tornado, Mattawoman, Maryland, April 5, 2011

This EF0 tornado ran 0.1 miles across Charles County on April 5, 2011, touching down at 4:48 AM EDT and reaching 50 yards wide. It killed nobody, and did $5,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  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.

The record

Rating
EF0
Date
April 5, 2011
Touchdown
4:48 AM EDT (08:48 UTC)
Lifted
4:49 AM EDT (08:49 UTC)
On the ground
1 minutes
Path length
0.1 miles (0.1 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
$5,000
County
Charles County
Touchdown point
38.652, -76.890
Lift-off point
38.653, -76.890
Record number
1104050248-01

What the Weather Service recorded

A strong cold front slowly traced through the area during the morning hours of the 5th. A southerly flow ahead of the front caused copious amounts of moisture to move into the region from the Atlantic Ocean and Gulf of Mexico. The deep moisture combined with a mid-level trough that was associated with the cold front to produce moderate amounts of instability. Lift from the cold front along with moderate instability triggered showers and thunderstorms across the area. ||Thunderstorms were able to mix down strong winds from aloft causing damaging wind gusts. Wind speeds that changed rapidly in speed and direction with height caused the stronger storms to produce isolated tornadoes.

A brief tornado struck the community of Marbella in northern Waldorf. A large pine tree was blown over into a house roof and several community trees were snapped. There was damage to a fence and there were many windblown outdoor objects.

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

The warnings

2 minutes of warning. NWS LWX issued a tornado warning for this county at 08:46 UTC, 2 minutes before the tornado touched down, in force until 09:15 UTC.

The county was under a tornado watch, issued at 06:20 UTC and running to 09:10 UTC.

Issued (UTC)ExpiredProductOffice
06:20 UTC09:10 UTCTornado WatchLWX
08:29 UTC09:20 UTCSevere Thunderstorm WarningLWX
08:38 UTC09:23 UTCSevere Thunderstorm WarningLWX
08:46 UTC09:15 UTCTornado WarningLWX
08:57 UTC09:13 UTCTornado WarningLWX
09:05 UTC09:11 UTCTornado WarningLWX

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 forecast that day

The Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 05:26 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 air that afternoon

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/Dulle, VA (KIAD), 00:00Z

8.8 hours before the tornado, 55 km from the path. April 5, 2011.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 00:00Z on 2011-04-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -69219, lifted condensation level 4112 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2011-04-05The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 284 square meters per square second, 0 to 6 km bulk shear 49 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-69219 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
4112 m above ground
0-6 km bulk shear
49 kt
0-1 km bulk shear
31 kt
0-1 km storm-relative helicity
284 m²/s²
0-3 km storm-relative helicity
328 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
7.5 K/km

Open this sounding in Storm Lab

Washington/Dulle, VA (KIAD), 12:00Z

3.2 hours after it, 55 km from the path. April 5, 2011.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2011-04-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -65986, lifted condensation level 668 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2011-04-05The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 61 square meters per square second, 0 to 6 km bulk shear 82 knots.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-65986 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
668 m above ground
0-6 km bulk shear
82 kt
0-1 km bulk shear
42 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

The surface observations

Andrews Afb (ADW), 18 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
06:55 UTC64.2259.18160° 14 kt995.6
07:55 UTC65.359170° 12 kt993.9
08:48 UTC6859250° 32 kt42995.6RA
08:49 UTC6859260° 31 kt42995.3TSRA
08:50 UTC66.259260° 27 kt42994.9TSRA
08:51 UTC66.260.8260° 22 kt42994.9+TSRA
08:52 UTC64.459260° 18 kt42994.9+TSRA
08:53 UTC64.459260° 18 kt42994.9+TSRA
08:55 UTC62.2459260° 15 kt42994.9+TSRA BR
08:56 UTC60.859260° 16 kt42994.9+TSRA BR
08:57 UTC60.859250° 15 kt42994.9+TSRA BR
08:58 UTC60.859250° 15 kt42995.3+TSRA BR
08:59 UTC60.857.2250° 14 kt32995.3+TSRA BR
09:00 UTC60.857.2250° 13 kt32995.3+TSRA BR
09:01 UTC60.857.2240° 13 kt22995.3TSRA BR
09:03 UTC5957.2240° 13 kt22994.9TSRA BR
09:04 UTC5957.2240° 12 kt22994.9RA BR
09:23 UTC5957.2210° 12 kt994.6
09:46 UTC5957.2210° 11 kt993.9-DZ
09:55 UTC58.6456.3210° 10 kt993.9-RA
10:08 UTC5957.2180° 9 kt992.6

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

The radar

The Sterling radar (KLWX), 63 km away, was scanning. The volume nearest the touchdown began at 08:49 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.

What was reported nearby

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

Time (UTC)ReportWhereCountyRemark
08:29 UTCTSTM WND DMGChevy ChaseMontgomery, MDTREE FELL ON AUTOMOBILE ON JONES MILL ROAD.
08:39 UTCTSTM WND DMG1 W Port Tobacco VillagCharles, MDTREE DOWN.
08:42 UTCTSTM WND DMGLandoverPrince Georges, MDTREE ON HOUSE.
08:44 UTCTSTM WND DMG1 Ene NorthwoodCharles, MDNUMEROUS TREES DOWN.
08:44 UTCTSTM WND DMG2 Ese Port TobaccoCharles, MDTELEPHONE POLE AND WIRES DOWN.
08:47 UTCTSTM WND DMG1 Ene NorthwoodCharles, MDTREE DOWN ON PORCH.
08:48 UTCTSTM WND DMG1 Ene NorthwoodCharles, MD16 TO 18 INCH DIAMETER PINE TREE ONTO A HOUSE
08:48 UTCTORNADO1 Ene NorthwoodCharles, MDA WEAK EF-0 TORNADO WITH PEAK WINDS OF 65 MPH BRIEFLY CAUSED SOME DAMAGE IN NORTH WALDORF BEFORE DISSIPATING. DAMAGE INCLUDED A LARGE PINE TREE PUSHED INTO A HOUSE ROOF AND SEVERAL ORNAMENTAL TREES SNAPPED.
08:55 UTCTORNADO1 Ene BowiePrince Georges, MD
09:01 UTCTSTM WND DMG1 Sse DunkirkCalvert, MDTREES DOWN. INTENSE WINDS REPORTED
09:03 UTCTSTM WND DMG1 Ssw Mount HarmonyCalvert, MDTREE DOWN ALONG SKINNERS TURN RD.
09:05 UTCTSTM WND DMG3 Ene Eagle HarborCalvert, MDTREE DOWN.
09:10 UTCTSTM WND DMG2 Nnw North BeachAnne Arundel, MDTREMENDOUS WIND BLEW DOWN SMALL LIMBS
09:20 UTCTSTM WND DMG1 Ese Saint Leonard CreCalvert, MDTREE DOWN.

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

This ground now

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

The other tornadoes of April 5, 2011

2 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 52:39 AM EDTEF2Dodge, GA3.15012$150,000
April 54:55 AM EDTEF0Anne Arundel, MD1.350$4,000

What this means

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.

Sources

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