Alert archive / North Dakota / Tornado Warnings in 1991

Tornado Warning 1, NWS Bismarck, ND

May 12, 1991Benson County, North Dakota

NWS Bismarck, ND issued this tornado warning at May 12, 1991, 6:05 PM CDT for Benson County, North Dakota. It was in force for 40 min. 1 report 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
May 12, 1991, 6:05 PM CDT (23:05 UTC)
Expired
May 12, 1991, 6:45 PM CDT
In force
40 min
Issued by
NWS Bismarck, ND
Area
Whole counties

County Benson County, ND

What was reported inside it

TimeReportWhereRemark
May 12, 6:30 PM CDTHail 1.75Benson, ND

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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 11.1 hours before the alert went out and 176 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, Bismarck Municip, ND at 12:00Z on 1991-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1247 joules per kilogram.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.
HodographHodograph, Bismarck Municip, ND at 12:00Z on 1991-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 187 square meters per square second.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.
Mixed-layer CAPE
1247 J/kg
Mixed-layer CIN
-145 J/kg
Mixed-layer LCL
1013 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
213 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KBIS 122305
TORBIS
NDC005-122345-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
TORNADO WARNING 
NATIONAL WEATHER SERVICE BISMARCK ND
605 PM CDT SUN MAY 12 1991

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING 
EFFECTIVE UNTIL 645 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY

   IN THE NORTHEAST PART OF NORTH DAKOTA
      BENSON

AT 600 PM CDT THE PUBLIC REPORTED A FUNNEL CLOUD 6 MILES NORTH
OF MINNEWAUKEN...OR 20 MILES WEST OF DEVILS LAKE. AT 555 PM CDT
GOLF BALL SIZED HAIL FELL AT MINNEWAUKEN. THIS STORM WAS MOVING
NORTH AT 25 MPH.

IF YOU ARE IN THE PATH OF THIS TORNADO...GO TO A BASEMENT SHELTER
IF AVAILABLE...OTHERWISE TO A CENTRAL INTERIOR ROOM ON THE LOWEST
FLOOR...STAY AWAY FROM WINDOWS.  ABANDON CARS AND MOBILE HOMES.

THIS STORM IS ACCOMPANIED BY DANGEROUS LIGHTNING...LARGE HAIL...
VERY HEAVY RAIN...AND DAMAGING STRAIGHT LINE WINDS.

 RSL

What forecasters said that day

The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, May 12, 2:44 PM CDT, 3 hours 21 minutes before
NDZ001>003-005-122030-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILLISTON ND
240 PM CDT SUN MAY 12 1991

...TORNADO WATCH IN EFFECT UNTIL 900 PM CDT FOR MOUNTRAIL COUNTY IN
NORTHWEST NORTH DAKOTA...

AT 235 PM CDT...NATIONAL WEATHER SERVICE RADAR IN WILLISTON INDICATED
STRONG THUNDERSTORMS 45 MILES NORTHEAST OF WILLISTON...ALONG THE
MOUNTRAIL/WILLIAMS COUNTY BORDER.  THESE THUNDERSTORMS WERE MOVING TO
THE NORTH AT 40 MILES AN HOUR.

THESE THUNDERSTORMS WILL PRODUCE DEADLY LIGHTNING STRIKES...GUSTY WINDS
...AND HEAVY DOWNPOURS.

RADAR AT 235 PM CDT WAS NOT SHOWING ANY SEVERE WEATHER BUT REMEMBER...
THUNDERSTORMS CAN AND SOMETIMES DO PRODUCE TORNADOES.

OTHER THUNDERSTORMS WEREr DEVELOPING OVER MCKENZIE AND WILLIAMS COUNTIES.

IF THESE THUNDERSTORMS MOVE INTO YOUR AREA...SEEK SHELTER IMMEDIATELY.

MARTIN
Special weather statement, May 12, 3:00 PM CDT, 3 hours 5 minutes before
NDZ001>018-122200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BISMARCK ND
255 PM CDT SUN MAY 12 1991

...TORNADO WATCH IN EFFECT FOR CENTRAL NORTH DAKOTA UNTIL 9PM CDT...

VERY UNSTABLE AIR HAS SPAWNED A THREAT OF SEVERE THUNDERSTORMS AND
TORNADOS OVER CENTRAL NORTH DAKOTA THIS AFTERNOON AND EVENING.

AT 255 PM CDT...RADARS SHOWED A BAND OF SCATTERED THUNDERSTORMS ABOUT
30 MILES WIDE EXTENDING FROM THE SOUTH DAKOTA BORDER SOUTH OF BISMARCK
ACROSS EASTERN LAKE SAKAKAWEA TO JUST SOUTHWEST OF MINOT. SOME OF THE
STORMS CONTAINED BRIEF HEAVY RAIN AND POSSIBLE HAIL. THEY WERE MOVING
NORTH ABOUT 30 MPH.

A COLD FRONT JUST WEST OF THIS BAND WILL MOVE EAST ACROSS CENTRAL
NORTH DAKOTA THIS AFTERNOON AND EVENING. IT WILL INCREASE THE RISK
OF SEVERE WEATHER. PERSONS IN CENTRAL NORTH DAKOTA SHOULD STAY ALERT FOR
POSSIBLE FUTURE WARNINGS.

LM
Special weather statement, May 12, 3:42 PM CDT, 2 hours 23 minutes before
NDZ001>003-005-122140-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILLISTON ND
340 PM CDT SUN MAY 12 1991

...TORNADO WATCH IN EFFECT UNTIL 900 PM CDT FOR MOUNTRAIL COUNTY IN
NORTHWEST NORTH DAKOTA...

AT 335 PM CDT...STRONG THUNDERSTORMS WERE OCCURRING 90 MILES NORTHEAST
OF WILLISTON...BETWEEN THE TOWNS OF AMBROSE AND COLUMBUS NORTH DAKOTA.
OTHER THUNDERSTORMS WERE SCATTERED ACROSS THE AREA.  THUNDERSTORMS WERE
MOVING TO THE NORTHWEST AT 35 MILES AN HOUR.

THESE THUNDERSTORMS MAY PRODUCE DEADLY LIGHTNING STRIKES...HAIL...GUSTY
WINDS...AND HEAVY RAIN.

NATIONAL WEATHER SERVICE RADAR AT 335 PM WAS NOT SHOWING ANY SEVERE
WEATHER BUT REMEMBER...THUNDERSTORMS ARE CAPABLE OF PRODUCING TORNADOES.

IF THUNDERSTORMS MOVE INTO YOUR AREA...SEEK SHELTER AS SOON AS POSSIBLE
...DO NOT DELAY.

MARTIN
Special weather statement, May 12, 4:24 PM CDT, 1 hour 41 minutes before
NDZ001>018-122300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BISMARCK ND
410 PM CDT SUN MAY 12 1991

...TORNADO WATCH IN EFFECT FOR CENTRAL NORTH DAKOTA UNTIL 9PM CDT...

AT 415 PM CDT...RADARS SHOWED STRONG THUNDERSTORMS IN SOUTH CENTRAL
NORTH DAKOTA IN THE COUNTIES OF BURLEIGH...MORTON AND SIOUX. ONE VERY
STRONG STORM PASSED OVER BISMARCK AT 4 PM CDT DROPPING MUCH MARBLE
SIZE HAIL AND A FEW HAIL STONES UP TO ONE INCH.

IN NORTH CENTRAL NORTH DAKOTA...A SEVERE THUNDERSTORM WARNING
CONTINUES IN EFFECT FOR MCHENRY COUNTY UNTIL 445 PM CDT. RADARS AT
415 PM CDT INDICATED A SEVERE THUNDERSTORM IN SOUTHWEST MCHENRY
COUNTY MOVING NORTH 30 MPH.

IN NEAIGHBORING NORTHEAST WARD COUNTY...MINOT AIR BASE REPORTED HAIL
ONE HALF INCH IN DIAMETER.
<
PERSONS THROUGHOUT CENTRAL NORTH DAKOTA SHOULD REMAIN ALERT FOR FUTURE
WARNINGS.

LM
Special weather statement, May 12, 4:48 PM CDT, 1 hour 17 minutes before
NDZ001>003-005-122140-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILLISTON ND
445 PM CDT SUN MAY 12 1991

...TORNADO WATCH IN EFFECT UNTIL 900 PM CDT FOR MOUNTRAIL COUNTY IN
NORTHWEST NORTH DAKOTA...

AT 440 PM CDT...STRONG THUNDERSTORMS CONTINUED TO DEVELOP OVER
NORTHWEST NORTH DAKOTA.  THE STRONGEST THUNDERSTORMS WERE LOCATED 35
MILES NORTHEAST OF WILLISTON IN NORTHEAST WILLIAMS COUNTY.
THUNDERSTORMS WERE MOVING TO THE NORTHWEST AT 35 MILES AN HOUR.

THESE THUNDERSTORMS MAY PRODUCE DEADLY LIGHTNING STRIKES...HAIL...GUSTY
WINDS...AND HEAVY RAIN.

NATIONAL WEATHER SERVICE RADAR AT 440 PM WAS NOT SHOWING ANY SEVERE
WEATHER BUT REMEMBER...THUNDERSTORMS ARE CAPABLE OF PRODUCING TOR<NADOES.

IF THUNDERSTORMS MOVE INTO YOUR AREA...SEEK SHELTER IMMEDIATELY...DO NOT
DELAY.

MARTIN
Special weather statement, May 12, 5:40 PM CDT, 25 minutes before
NDZ001>003-005-122340-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILLISTON ND
540 PM CDT SUN MAY 12 1991

...TORNADO WATCH IN EFFECT UNTIL 900 PM CDT FOR MOUNTRAIL COUNTY IN
NORTHWEST NORTH DAKOTA...

AT 540 PM CDT...STRONG THUNDERSTORMS CONTINUED TO DEVELOP OVER
NORTHWEST NORTH DAKOTA.  THE STRONGEST THUNDERSTORMS WERE LOCATED 55
MILES NORTH OF WILLISTON IN EAST CENTRAL DIVIDE COUNTY...10 MILES NORTH
TO THE TOWN OF AMBROSE. ANOTHER STRONG THUNDERSTORM WAS LOCATED 50
MILES SOUTHEAST OF WILLISTON...OR 25 MILES SOUTH OF WATFORD CITY.

THESE THUNDERSTORMS WERE MOVING TO THE NORTH AT 35 MILES AN HOUR AND
ARE CAPABLE OF PRODUCING DEADLY LIGHTNING STRIKES...SMALL HAIL...GUSTY
WINDS...AND HEAVY RAIN.

NATIONAL WEATHER SERVICE RADAR AT 540 PM WAS NOT SHOWING ANY SEVERE
WEATHER IN THE TORNADO WATCH AREA IN MOUNTRAIL COUNTY.

IF THESE STORMS MOVE INTO YOUR AREA...MOVE TO A SAVE SHELTER.

RICHMOND

The office that day

Everything else NWS Bismarck, ND issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 12, 3:43 PM CDTSevere Thunderstorm WarningBISMcHenry62 min
May 12, 4:28 PM CDTSevere Thunderstorm WarningBISBurleigh47 min
May 12, 5:19 PM CDTSevere Thunderstorm WarningBISBenson41 min
May 12, 6:12 PM CDTSevere Thunderstorm WarningBISEmmons33 min
May 12, 6:23 PM CDTSevere Thunderstorm WarningBISLogan37 min

Nearby

Tornado Warnings in North Dakota, 1991Every tornado warning in 1991Tornadoes in 1991

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.