F1 tornado, Glenmont, Maryland, June 21, 2000

1. F040 to 72 mph

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

2. F173 to 112 mphthis tornado

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

3. F2113 to 157 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. F3158 to 206 mph

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

5. F4207 to 260 mph

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

6. F5261 to 318 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

F1

Date

June 21, 2000

Touchdown

10:10 PM EDT (02:10 UTC)

Path length

1.0 miles (1.6 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

Property damage

$250,000

County

Montgomery County

Touchdown point

39.080, -77.070

Lift-off point

39.100, -77.000

Record number

989

Thunderstorms which contained winds in excess of 55 MPH, heavy rainfall, and large hail developed ahead of a cold front during the evening of the 21st. The line of storms that moved across Montgomery and Prince George's Counties produced two tornadoes. The first tornado touched down in the Aspen Hill area of Montgomery County along Colesville Manor Drive. It move east across Northwest Branch Park and onto Scott Drive, Mills Avenue, Notley Street, and Paula Lynn Drive, then dissipated 1 mile north of Colesville. The F1 tornado was on the ground for 1 mile and was 30 yards wide . It downed numerous trees, including one which fell onto a house and another onto a shed. The second tornado, nearly 150 yards wide, touched down just east of Laurel near Route 197 and the Patuxent Greens Country Club. It damaged a garage door, tore an awning, and lifted shingles on golf course property, in addition to knocking down over 80 large trees. The F1 tornado continued east for one mile downing several other trees before dissipating near the Patuxent River. In addition to the tornado damage, straight line winds in excess of 55 MPH also damaged trees, power lines, and structures in Montgomery and Prince George's Counties. An apartment complex in Silver Spring suffered roof damage, shattered windows, ripped gutters, and damaged cinder block walls. Downed fences and several cars damaged by fallen trees were found nearby. Tree damage was also reported in Gaithersburg, the Rock Creek Valley neighborhood, Wheaton, and Laurel. In Howard County, high winds blew in a window and snapped trees south of Columbia. Winds estimated between 60 and 75 MPH downed numerous trees and power lines across northern Anne Arundel County, including the communities of Odenton, Glen Burnie, Crownsville, and Pasadena. In Frederick County, 1.75 inches of rain fell in Wolfsville and 1.57 inches was recorded in Frederick.

Numerous trees were downed or snapped, several cars were damaged by trees and debris. Several apartment roofs, a wall, and a fence were damaged. Trim and siding on homes were also damaged.

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.

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. The outlook in force was issued at 00:48 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.

The Sterling radar (KLWX), 41 km away, was scanning. The volume nearest the touchdown began at 02:07 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.

The live radar over the trackEvery 2000 tornado in MarylandEvery tornado in Maryland since 1950Warnings in force in Maryland nowThe forecast where you are

3 more were confirmed in the United States that day.

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.