Alert archive / Iowa / Tornado Warnings in 1997

Tornado Warning 5, NWS Sioux Falls, SD

July 7, 1997Lyon County, Sioux County, Iowa

NWS Sioux Falls, SD issued this tornado warning at Jul 7, 1997, 5:01 PM CDT for Lyon County, Sioux County, Iowa. It was in force for 44 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 7, 1997, 5:01 PM CDT (22:01 UTC)
Expired
Jul 7, 1997, 5:45 PM CDT
In force
44 min
Issued by
NWS Sioux Falls, SD
Area
Whole counties

Counties Lyon County, IA, Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 59 km from the middle of the area, began a volume at 22:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Jul 7, 5:20 PM CDTThunderstorm Wind 52Hawarden, IA
Jul 7, 5:25 PM CDTTornado F0Inwood, IAA brief tornado observed by sheriff's office personnel resulted in no reported damage.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 7, 4:00 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.0 hours before the alert went out and 213 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 1997-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.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.
HodographHodograph, Omaha, NE at 12:00Z on 1997-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 square meters per square second.1939Sfc1 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.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
929 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KFSD 072202 RRA
TORFSD
IAC119-167-072245-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
501 PM CDT MON JUL 7 1997

* TORNADO WARNING FOR
  LYON COUNTY - NORTHWESTERN IOWA
  WESTERN SIOUX COUNTY - NORTHWESTERN IOWA

* UNTIL 545 PM CDT
 
* SOME AREAS AFFECTED
  ROCK VALLEY              AROUND 455 PM CDT
  ROCK RAPIDS              AROUND 505 PM CDT
  GEORGE                   AROUND 515 PM CDT
  MATLOCK                  AROUND 520 PM CDT
  SHELDON                  AROUND 525 PM CDT

* AT 457 PM CDT...NATIONAL WEATHER SERVICE SPOTTERS REPORTED A
  TORNADO 20 MILES SOUTHEAST OF SIOUX FALLS  OR 9 MILES SOUTHWEST OF
  ALVORD MOVING EAST AT 45 MPH.

AT 500 AM A TORNADO WAS REPORTED NEAR CANTON SOUTH DAKOTA.
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING.  AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR
LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

IF YOU ARE IN THE PATH OF2 A TORNADO...THE SAFEST PLACE IN A HOME OR
BUSINESS IS AN INTERIOR ROOM ON THE LOWEST FLOOR POSSIBLE.  AVOID
WINDOWS.

BLOOM

&

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 5:40 PM CDTSevere Thunderstorm WarningFSDPlymouth30 min
Jul 7, 6:15 PM CDTSevere Thunderstorm WarningFSDPlymouth30 min
Jul 7, 6:47 PM CDTSevere Thunderstorm WarningFSDPlymouth33 min
Jul 7, 6:47 PM CDTTornado WarningFSDPlymouth33 min

Nearby

Tornado Warnings in Iowa, 1997Every tornado warning in 1997Tornadoes in 1997

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.