Tornadoes · United States · Louisiana · 2021

EF1 tornado, Saint Tammany Parish, Louisiana, August 29, 2021

This EF1 tornado ran 4.9 miles across Saint Tammany Parish on August 29, 2021, touching down at 6:33 PM CDT and reaching 175 yards wide. It killed nobody, and did $25,000 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 mph

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

  2. EF186 to 110 mphthis tornado

    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
EF1
Date
August 29, 2021
Touchdown
6:33 PM CDT (23:33 UTC)
Lifted
6:38 PM CDT (23:38 UTC)
On the ground
5 minutes
Path length
4.9 miles (7.9 km)
Path width
175 yards (160 m)
Deaths
0
Injuries
0
Property damage
$25,000
County
Saint Tammany Parish
Touchdown point
30.211, -89.773
Lift-off point
30.230, -89.853
Record number
2108291733-01

The damage survey

33 damage points were recorded along this path by NWS LIX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 88 mph.

  • Partial collapse of roof and roofing material.
  • Metal roof off of a house on Lakeview Drive.
  • Partial roof material missing from house. Time estimated from radar.
  • some roof material missing on two houses. Time estimated from radar.

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

The warnings

8 minutes of warning. NWS LIX issued a tornado warning for this county at 23:25 UTC, 8 minutes before the tornado touched down, in force until 00:00 UTC.

The county was under a tornado watch, issued at 11:11 UTC and running to 23:50 UTC.

Issued (UTC)ExpiredProductOffice
11:11 UTC23:50 UTCTornado WatchLIX
12:00 UTC21:38 UTCFlash Flood WatchLIX
12:00 UTC07:47 UTCFlood WatchLIX
23:09 UTC07:30 UTCFlash Flood WarningLIX
23:21 UTC15:45 UTCFlash Flood WarningLIX
23:25 UTC00:00 UTCTornado WarningLIX
23:50 UTC10:54 UTCTornado WatchLIX
23:54 UTC00:30 UTCTornado WarningLIX
01:22 UTC02:00 UTCTornado WarningLIX
01:49 UTC15:08 UTCFlood WarningLIX
04:50 UTC08:00 UTCFlash Flood WarningLIX

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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:50 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 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.

Slidell Radar S, LA (KSIL), 12:00Z

11.6 hours before the tornado, 11 km from the path. August 29, 2021.

Skew-T log-pSkew-T log-p diagram, Slidell Radar S, LA at 12:00Z on 2021-08-29Temperature 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 -89790, lifted condensation level 3256 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Slidell Radar S, LA at 12:00Z on 2021-08-29The 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 -55 square meters per square second, 0 to 6 km bulk shear 37 knots.193958Sfc1 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
-89790 J/kg
Surface CAPE
543 J/kg
Mixed-layer LCL
3256 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
-55 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.3
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

Slidell Radar S, LA (KSIL), 00:00Z

0.4 hours after it, 11 km from the path. August 30, 2021.

Skew-T log-pSkew-T log-p diagram, Slidell Radar S, LA at 00:00Z on 2021-08-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 25 joules per kilogram, CIN -2, lifted condensation level 679 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°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, Slidell Radar S, LA at 00:00Z on 2021-08-30The 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 36 square meters per square second, 0 to 6 km bulk shear 41 knots.1939587897Sfc1 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
25 J/kg
Mixed-layer CIN
-2 J/kg
Surface CAPE
65 J/kg
Mixed-layer LCL
679 m above ground
0-6 km bulk shear
41 kt
0-1 km bulk shear
6 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.0 K/km

Open this sounding in Storm Lab

The surface observations

Slidell (ASD), 14 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:35 UTC110° 20 kt291003+RA BR
21:40 UTC100° 22 kt401003+RA BR
21:42 UTC787490° 21 kt401002.7+RA BR
21:45 UTC90° 18 kt271002.7+RA BR
21:50 UTC90° 18 kt311002.4+RA BR
21:50 UTC7773.4100° 19 kt331002.4+RA BR
21:53 UTC777490° 23 kt411002.4+RA BR
21:55 UTC100° 21 kt281002.4RA BR
22:00 UTC90° 17 kt271002RA BR
22:01 UTC777490° 17 kt411002.4+RA BR
22:05 UTC100° 15 kt221002.4+RA BR
22:10 UTC110° 16 kt241002.4+RA BR
22:12 UTC7774100° 20 kt401002+RA BR
22:15 UTC100° 24 kt311002+RA BR
22:20 UTC110° 22 kt331002+RA BR
22:25 UTC100° 20 kt271002+RA BR
22:30 UTC100° 17 kt301001.7+RA BR
22:35 UTC90° 22 kt301001.4+RA BR
22:40 UTC90° 21 kt1001.4+RA BR
22:45 UTC120° 22 kt321001.7+RA BR
22:50 UTC120° 24 kt1002+RA BR
22:53 UTC7874110° 25 kt511001.7+RA BR
22:55 UTC110° 19 kt311001+RA BR
23:00 UTC90° 19 kt361001+RA BR
23:05 UTC110° 22 kt341000.7+RA BR
23:10 UTC110° 22 kt331000.7+RA BR
23:15 UTC100° 20 kt341000.3+RA BR
23:20 UTC100° 18 kt1000.3+RA BR
23:21 UTC7875110° 18 kt371000.3+RA BR
23:25 UTC100° 24 kt301000.3+RA BR
23:30 UTC100° 19 kt281000+RA BR
23:35 UTC110° 18 kt1000.3+RA BR
23:40 UTC110° 26 kt401000.3+RA BR
23:45 UTC100° 29 kt371000+RA BR
23:49 UTC7773.4110° 26 kt461000+RA BR
23:50 UTC100° 27 kt471000.3+RA BR
23:53 UTC7774110° 24 kt491000.3+RA BR
23:55 UTC100° 22 kt281000.3+RA BR
00:00 UTC7774100° 22 kt391000+RA BR
00:00 UTC100° 22 kt311000+RA BR
00:04 UTC7775120° 23 kt431000+RA BR
00:05 UTC120° 21 kt351000+RA BR
00:07 UTC7775110° 21 kt431000+RA BR
00:10 UTC 22 kt371000+RA BR
00:15 UTC 27 kt431000+RA BR
00:20 UTC100° 23 kt37999.7RA BR
00:25 UTC 20 kt38999.7+RA BR
00:30 UTC 30 kt45999.3+RA BR
00:32 UTC7775110° 25 kt47999.7+RA BR
00:35 UTC 28 kt41999.3+RA BR
00:40 UTC110° 24 kt37999.3+RA BR
00:45 UTC120° 28 kt37999.3+RA BR
00:50 UTC110° 28 kt39998.6+RA BR
00:53 UTC7775110° 28 kt55998.6+RA BR
00:55 UTC110° 23 kt38999+RA BR
01:00 UTC110° 23 kt32999.3+RA BR
01:05 UTC110° 28 kt33999+RA BR
01:10 UTC120° 30 kt999+RA BR
01:15 UTC110° 23 kt43999.3+RA BR
01:20 UTC120° 37 kt56999.7+RA BR
01:25 UTC120° 29 kt44999.7+RA BR
01:30 UTC120° 29 kt46999.7+RA BR

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

What was reported nearby

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

Time (UTC)ReportWhereCountyRemark
22:10 UTCHURRICANE5 Sse East New OrleansSt. Bernard, LAWEATHERFLOW OBSERVATION AT BAYOU BEINVENUE SUSTAINED WINDS OF 82 MPH WITH GUST UP TO 99.;.
22:11 UTCTROPICAL STORM2 Nw KennerJefferson, LANEW ORLEANS INTERNATIONAL AIRPORT (KMSY) SUSTAINED WINDS 62 MPH WITH GUSTS TO 81 MPH.
22:16 UTCTROPICAL STORM6 Wsw East New OrleansGmz530, LALAKEFRONT AIRPORT (KNEW) SUSTAINED WINDS OF 66 MPH WITH GUSTS UP TO 86 MPH.
22:30 UTCTROPICAL STORM4 Ne LaplaceGmz530, LAFRENIER LANDING SUSTAINED 62 MPH GUST 84 MPH.
22:51 UTCTROPICAL STORM1 Ne WaggamanJefferson, LAJEFFERSON PARISH WEATHERFLOW OBSERVATION RECORDED SUSTAINED WINDS OF 53 MPH AND A GUST TO 82 MPH.
23:01 UTCTROPICAL STORM1 Ssw MandevilleGmz530, LAWEATHERFLOW OBSERVATION AT MANDEVILLE SUSTAINED WINDS 37 MPH WITH A PEAK GUST OF 75 MPH.
23:02 UTCTROPICAL STORM12 Ssw MandevilleGmz530, LAWEATHERFLOW OBSERVATION AT MID LAKE ON THE CASUEWAY NOW SUSTAINED 64 MPG GUST TO 86 MPH.
23:33 UTCTORNADO2 Se Eden IsleSt. Tammany, LAA TORNADO TOUCHED DOWN IN EDEN ISLE JUST EAST OF I-10. THE FIRST SIGN OF VISIBLE DAMAGE WAS TO A VACANT CONDOMINIUM COMPLEX ON LAKE SHORE BLVD EAST. THE ROOF TO TWO OF THE BUILDINGS WERE PARTIALLY TORN WITH CONSTRUCTION
01:37 UTCHIGH SUST WINDS 621 Nnw KennerJefferson, LAASOS STATION KMSY NEW ORLEANS INTL-LOUIS ARMSTRONG. WIND SPEEDS OF 62 MPH. GUSTS TO 90 MPH AT NEW ORLEANS INTERNATIONAL AIRPORT.
01:56 UTCTORNADO1 Sse Eden IsleSt. Tammany, LAA BRIEF TORNADO TOUCHED DOWN IN EDEN ISLE ON MARINA DR WHERE SEVERAL HOUSES SUSTAINED ROOF AND FENCE DAMAGE. UPROOTED TREES AND ADDITIONAL PROPERTY DAMAGE WERE CAPTURED BY NOAA AERIAL IMAGERY IN THE TORNADO S PATH ALONG

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

This ground now

The live radar over the trackEvery 2021 tornado in LouisianaEvery tornado in Louisiana since 1950Warnings in force in Louisiana nowThe forecast where you are

The other tornadoes of August 29, 2021

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
August 296:23 AM CDTEF1Harrison, MS2.1150$50,000
August 296:25 AM CDTEF1Hancock, MS1.7150$10,000
August 295:15 PM CDTEF0Harrison, MS0.750$100,000
August 296:59 PM CDTEF0Hancock, MS10.675$50,000
August 298:56 PM CDTEF0Saint Tammany Parish, LA0.9100$100,000
August 2910:11 PM CDTEF0Hancock, MS3.3200$250,000
August 2910:15 PM CDTEF0Hancock, MS2.9200$20,000
August 2910:37 PM CDTEF0Harrison, MS0.575$100,000

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.