Tornadoes · United States · Minnesota · 1998

F3 tornado, Courtland to St Peter, Minnesota, March 29, 1998

From Courtland to St Peter, this F3 tornado ran 12.0 miles across Nicollet County on March 29, 1998, touching down at 5:18 PM CST and reaching 2,200 yards wide. It killed 1 person, and did $120 million of property damage.

The rating scale

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

  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 mph

    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 mphthis tornado

    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.

The record

Rating
F3
Date
March 29, 1998
Touchdown
5:18 PM CST (23:18 UTC)
Path length
12.0 miles (19.3 km)
Path width
2,200 yards (2012 m)
Deaths
1
Injuries
0
Property damage
$120 million
County
Nicollet County
Touchdown point
44.280, -94.170
Lift-off point
44.330, -93.950
Record number
789

What the Weather Service recorded

See narrative for Brown county.

Tornado made a direct hit on the city of St. Peter and Gustavius Adolphus College. All major buildings on campus suffered varying degrees of damage. The spire on Christ Chapel snapped in half. 70% of the windows on campus were broken. 500 homes were destroyed in St. Peter, 1,700 were damaged. Over 1,000 trees uprooted. One person killed just outside St. Peter when the tornado struck a vehicle. St. Peter Catholic Church destroyed. Hospital severely damaged. Roof ripped off library. 25% of books lost. Debris from St. Peter found 50 miles away in southern suburbs of the Twin Cities. 60 rural homes and farms damaged or destroyed from Courtland to St. Peter. Rural damage estimated at 6.5 million.

The deaths

1 direct deaths are recorded for this tornado, each with what Storm Data knows of it.

AgeSexWhereKind
6MVehicle/Towed TrailerDirect

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

The warnings

22 minutes of warning. NWS MPX issued a tornado warning for this county at 22:56 UTC, 22 minutes before the tornado touched down, in force until 23:55 UTC.

Issued (UTC)ExpiredProductOffice
20:27 UTC21:15 UTCSevere Thunderstorm WarningMPX
22:56 UTC23:55 UTCTornado WarningMPX
23:47 UTC00:35 UTCTornado WarningMPX

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 Moderate Risk. The outlook in force was issued at 11:07 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.

Minneapolis, MN (KMPX), 12:00Z

11.3 hours before the tornado, 71 km from the path. March 29, 1998.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 1998-03-29Temperature 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 -70152, lifted condensation level 551 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, Minneapolis, MN at 12:00Z on 1998-03-29The 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 160 square meters per square second, 0 to 6 km bulk shear 46 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
-70152 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
551 m above ground
0-6 km bulk shear
46 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
160 m²/s²
0-3 km storm-relative helicity
251 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
3.8 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KMPX), 00:00Z

0.7 hours after it, 71 km from the path. March 30, 1998.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 1998-03-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 625 joules per kilogram, CIN -97, lifted condensation level 529 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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, Minneapolis, MN at 00:00Z on 1998-03-30The 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 499 square meters per square second, 0 to 6 km bulk shear 79 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
625 J/kg
Mixed-layer CIN
-97 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
529 m above ground
0-6 km bulk shear
79 kt
0-1 km bulk shear
44 kt
0-1 km storm-relative helicity
499 m²/s²
0-3 km storm-relative helicity
565 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.0
0-3 km lapse rate
3.4 K/km

Open this sounding in Storm Lab

The surface observations

Mankato (MKT), 15 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
21:31 UTC62.659140° 10 kt994.6
22:15 UTC64.460.8180° 10 kt15994.2
22:35 UTC66.260.8180° 7 kt993.6
22:55 UTC64.460.8140° 7 kt993.6
23:11 UTC64.460.8110° 11 kt992.6
23:31 UTC66.260.8180° 22 kt31991.2
23:56 UTC62.653.6310° 21 kt30994.2
00:15 UTC57.253.6300° 10 kt994.6
00:30 UTC57.255.4320° 7 kt994.6
01:12 UTC57.255.4160° 6 kt994.9

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

The radar

The Minneapolis radar (KMPX), 72 km away, was scanning. The volume nearest the touchdown began at 23:18 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.

This ground now

The live radar over the trackEvery 1998 tornado in MinnesotaEvery tornado in Minnesota since 1950Warnings in force in Minnesota nowThe forecast where you are

The other tornadoes of March 29, 1998

16 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
March 293:23 PM CSTF2Nobles, MN0.180$400,000
March 293:25 PM CSTF0Nobles, MN0.150$10,000
March 293:28 PM CSTF0Nobles, MN0.150$50,000
March 293:35 PM CSTF2Nobles, MN0.180$200,000
March 293:45 PM CSTF1Nobles, MN0.150$100,000
March 293:50 PM CSTF4Murray, MN73.51,500119$75 million
March 293:55 PM CSTF1Murray, MN0.150$50,000
March 295:07 PM CSTF0Wabasha, MN1.550
March 295:15 PM CSTF0Buffalo, WI4.050
March 295:35 PM CSTF3Le Sueur, MN6.02,200
March 295:48 PM CSTF2Le Sueur, MN17.01,7602$20 million
March 296:09 PM CSTF1Rice, MN0.1200
March 296:16 PM CSTF2Rice, MN5.0440$20 million
March 296:25 PM CSTF2Dakota, MN3.0440
March 296:43 PM CSTF0Dakota, MN1.0100
March 297:28 PM CSTF0Lincoln, WI4.580$10,000

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.