Tornadoes · United States · Maryland · 2011
EF0 tornado, Evna, Maryland, April 28, 2011
This EF0 tornado ran 1.1 miles across Baltimore County on April 28, 2011, touching down at 9:54 AM EDT and reaching 75 yards wide. It killed nobody, and did $1,000 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.
EF065 to 85 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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 28, 2011
- Touchdown
- 9:54 AM EDT (13:54 UTC)
- Lifted
- 9:55 AM EDT (13:55 UTC)
- On the ground
- 1 minutes
- Path length
- 1.1 miles (1.8 km)
- Path width
- 75 yards (69 m)
- Deaths
- 0
- Injuries
- 0
- Property damage
- $1,000
- County
- Baltimore County
- Touchdown point
- 39.598, -76.705
- Lift-off point
- 39.599, -76.704
- Record number
- 1104280754-01
What the Weather Service recorded
A strong cold front slowly passed through the region during the morning and early afternoon hours of the 28th. A southerly flow ahead of the front caused deep moisture over the area. The deep moisture combined with a mid-level trough to produce moderate amounts of instability. The cold front combined with the instability to trigger showers and thunderstorms. Some thunderstorms were able to mix down strong winds from aloft. ||Low level wind speed and direction changed rapidly with height causing tornadoes to develop in some of the stronger thunderstorms.
An aerial survey conducted by Baltimore county showed that a tornado touched down briefly just north of Evna Road in a heavily wooded area. The tornado snapped and uprooted about two dozen trees and down large branches.
From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.
The warnings
No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.
The county was under a tornado watch, issued at 11:41 UTC and running to 16:28 UTC.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 22:19 UTC | 04:42 UTC | Tornado Watch | LWX |
| 04:42 UTC | 11:41 UTC | Tornado Watch | LWX |
| 11:41 UTC | 16:28 UTC | Tornado Watch | LWX |
| 11:51 UTC | 16:29 UTC | Flash Flood Watch | LWX |
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 Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 12:59 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.
Phillips Aaf/Abe, MD (KAPG), 12:00Z
1.9 hours before the tornado, 54 km from the path. April 28, 2011.
- Mixed-layer CAPE
- 482 J/kg
- Mixed-layer CIN
- -47 J/kg
- Surface CAPE
- 487 J/kg
- Mixed-layer LCL
- 670 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 371 m²/s²
- 0-3 km storm-relative helicity
- 401 m²/s²
- Significant tornado parameter
- 1.3
- Supercell composite
- 5.5
- 0-3 km lapse rate
- 5.4 K/km
The surface observations
Westminster (DMW), 26 km from the path, in the two hours either side.
| Time (UTC) | Temp (°F) | Dew point (°F) | Wind | Gust (kt) | Pressure (mb) | Weather |
|---|---|---|---|---|---|---|
| 12:10 UTC | 69.8 | 66.2 | 190° 11 kt | 18 | 1003.4 | -RA |
| 12:31 UTC | 71.6 | 66.2 | 180° 14 kt | 22 | 1003 | |
| 12:52 UTC | 71.6 | 66.2 | 250° 19 kt | 28 | +RA | |
| 13:13 UTC | 69.8 | 66.2 | 270° 13 kt | 18 | +RA | |
| 13:34 UTC | 68 | 64.4 | 260° 8 kt | +RA | ||
| 13:55 UTC | 68 | 64.4 | 210° 9 kt | RA | ||
| 14:13 UTC | 66.2 | 62.6 | 240° 6 kt | -RA | ||
| 14:37 UTC | 66.2 | 60.8 | 250° 9 kt | -RA | ||
| 14:58 UTC | 66.2 | 60.8 | 250° 8 kt | |||
| 15:19 UTC | 66.2 | 60.8 | 250° 9 kt | 15 | ||
| 15:40 UTC | 66.2 | 60.8 | 250° 6 kt | 1005.4 |
From the Iowa Environmental Mesonet's archive of airport observations.
The radar
The Sterling radar (KLWX), 97 km away, was scanning. The volume nearest the touchdown began at 13:56 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) | Report | Where | County | Remark |
|---|---|---|---|---|
| 11:20 UTC | TSTM WND GST 63 | 2 Ene New Market | Frederick, MD | |
| 11:46 UTC | TORNADO | 1 Ese Westminster | Carroll, MD | EF-0 TORNADO. PEAK WINDS 65 MPH. PATH LENGTH 0.6 MILE. PATH WIDTH 50 YARDS. |
| 12:09 UTC | TORNADO | 2 Ese Hampstead | Baltimore, MD | EF-0 TORNADO. PEAK WINDS 65 MPH. PATH LENGTH 1.1 MILES. PATH WIDTH 50 YARDS. |
| 12:30 UTC | FLASH FLOOD | Libertytown | Frederick, MD | NORTH AND SOUTH STREETS FLOODED AND CLOSED BETWEEN ROUTE 75 AND TRAMMELS ALLEY. |
| 13:54 UTC | TORNADO | 2 Wnw Hereford | Baltimore, MD | BRIEF TOUCHDOWN IN WOODED AREA NORTH OF EVNA RD. DAMAGE WAS ALL TO TREES WITH NEARLY TWO DOZEN TREES UPROOTED AND OR TOPPED. RATED EF-O WITH MAX WINDS OF 70 MPH. WIDTH OF 75 YARDS. DURATION 1 MINUTE. |
| 14:09 UTC | FLOOD | 1 N Emmitsburg | Frederick, MD | IRISHTOWN ROAD CLOSED AT THE CREEK NEAR THE PENNSYLVANIA LINE DUE TO FLOODING. |
| 14:09 UTC | FLASH FLOOD | Libertytown | Frederick, MD | ONE LANE OF ROUTE 26 FLOODED AND CLOSED AT ROUTE 75 IN LIBERTYTOWN. |
| 16:07 UTC | FLASH FLOOD | 4 Nne Westminster | Carroll, MD | BEAR BRANCH CREEK OUT OF ITS BANKS |
| 16:19 UTC | FLOOD | 2 Wsw Union Bridge | Frederick, MD | TWO ROADS CLOSED IN THE UNION BRIDGE AREA. |
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 28, 2011
39 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| April 28 | 2:12 AM EDT | EF2 | Rockingham, VA | 33.5 | 400 | $450,000 | ||
| April 28 | 2:17 AM EDT | EF1 | Augusta, VA | 4.0 | 150 | $100,000 | ||
| April 28 | 2:20 AM EDT | EF1 | Huntingdon, PA | 2.9 | 50 | $10,000 | ||
| April 28 | 2:50 AM EDT | EF1 | Putnam, GA | 6.7 | 200 | $1.0 million | ||
| April 28 | 2:53 AM EDT | EF1 | Juniata, PA | 8.5 | 100 | $25,000 | ||
| April 28 | 3:01 AM EDT | EF1 | Rockingham, VA | 0.9 | 50 | $50,000 | ||
| April 28 | 3:20 AM EDT | EF2 | Chenango, NY | 7.4 | 400 | $625,000 | ||
| April 28 | 3:22 AM EDT | EF1 | Caldwell, NC | 4.5 | 100 | 1 | ||
| April 28 | 3:33 AM EDT | EF1 | Alexander, NC | 4.3 | 75 | |||
| April 28 | 3:39 AM EDT | EF1 | Warren, GA | 7.8 | 440 | $1.0 million | ||
| April 28 | 3:45 AM EDT | EF0 | Frederick, VA | 4.3 | 175 | $25,000 | ||
| April 28 | 3:55 AM EDT | EF1 | Rockingham, VA | 2.6 | 150 | $75,000 | ||
| April 28 | 3:58 AM EDT | EF1 | Chenango, NY | 3.4 | 150 | $75,000 | ||
| April 28 | 4:58 AM EDT | EF1 | Chenango, NY | 3.5 | 100 | $50,000 | ||
| April 28 | 5:04 AM EDT | EF1 | Herkimer, NY | 2.9 | 250 | |||
| April 28 | 5:50 AM EDT | EF0 | Susquehanna, PA | 1.0 | 80 | $40,000 | ||
| April 28 | 4:50 AM CDT | EF1 | Jackson, FL | 3.0 | 150 | $500,000 | ||
| April 28 | 5:55 AM EDT | EF2 | York, PA | 2.6 | 100 | $50,000 | ||
| April 28 | 6:20 AM EDT | EF1 | Lebanon, PA | 1.9 | 100 | $10,000 | ||
| April 28 | 6:30 AM EDT | EF2 | Lebanon, PA | 1.1 | 200 | $15,000 | ||
| April 28 | 6:45 AM EDT | EF0 | Montgomery, MD | 0.8 | 50 | $2,000 | ||
| April 28 | 7:37 AM EDT | EF0 | Carroll, MD | 0.7 | 50 | $5,000 | ||
| April 28 | 7:37 AM EDT | EF1 | Calhoun, SC | 4.7 | 440 | $250,000 | ||
| April 28 | 7:50 AM EDT | EF1 | Sumter, SC | 10.8 | 220 | $48,000 | ||
| April 28 | 8:09 AM EDT | EF0 | Baltimore, MD | 1.1 | 50 | $5,000 | ||
| April 28 | 8:18 AM EDT | EF0 | Sumter, SC | 1.6 | 80 | $18,000 | ||
| April 28 | 10:15 AM EDT | EF1 | Hanover, VA | 2.5 | 150 | $25,000 | ||
| April 28 | 11:25 AM EDT | EF1 | Saint Mary's, MD | 3.4 | 150 | $35,000 | ||
| April 28 | 11:41 AM EDT | EF0 | Calvert, MD | 1.7 | 50 | $7,000 | ||
| April 28 | 3:00 PM EDT | EF1 | Duplin, NC | 1.4 | 100 | $10,000 | ||
| April 28 | 3:43 PM EDT | EF0 | Columbus, NC | 0.6 | 20 | $27,000 | ||
| April 28 | 4:07 PM EDT | EF1 | Pender, NC | 0.3 | 60 | $66,000 | ||
| April 28 | 4:10 PM EDT | EF0 | Pender, NC | 6.3 | 50 | $33,000 | ||
| April 28 | 4:20 PM EDT | EF0 | Craven, NC | 0.1 | 50 | |||
| April 28 | 4:22 PM EDT | EF0 | Glynn, GA | 0.0 | 1 | |||
| April 28 | 4:29 PM EDT | EF1 | Pender, NC | 3.1 | 60 | $105,000 | ||
| April 28 | 4:30 PM EDT | EF0 | Martin, NC | 0.1 | 30 | |||
| April 28 | 4:38 PM EDT | EF0 | Pender, NC | 0.2 | 30 | $12,000 | ||
| April 28 | 5:23 PM EDT | EF0 | Beaufort, NC | 0.3 | 30 |
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.