Summary

A major tornado outbreak occurred across western Oklahoma during the afternoon and early evening of October 9th, 2001. Five supercell thunderstorms produced a total of 19 confirmed tornadoes. Three of the tornadoes were rated F3, making this the strongest tornado outbreak in Oklahoma for the month of October, and the most significant Oklahoma tornado outbreak since May 3, 1999. A brief review of the strongest tornadoes during the event follows.

The first F3 tornado developed in northeast Beckham County, on the northeast edge of Elk City, and tracked northeastward for 11 miles before dissipating. As the tornado entered Custer County, a home comprised of wood frames with a brick exterior had most of its interior and exterior walls destroyed. The tornado then continued across an unpopulated area, causing major damage to trees and fences, before dissipating 2.5 miles west of Foss Dam.

The second F3 tornado developed in Washita County, near Cordell. The Oklahoma State Emergency Management Office estimated that 477 single-family homes were damaged, 132 considered uninhabitable. In addition, 40 businesses were damaged, 22 considered uninhabitable. Damage was estimated near $1 million, and nine injuries were reported.

The last F3 tornado developed in Kiowa County and produced F3 damage soon after entering Washita County. Several vehicles and large pieces of farm equipment were tossed and destroyed. About 4 miles north-northeast of Mountain View, 3 homes suffered major damage, with one home incurring damage rated at F3. As the tornado continued northeastward, more F3 damage was inflicted on a farm, where a house and several barns and outbuildings were leveled. A 10,000 gallon diesel tank ended up in an open field about one-quarter mile away from its original position.

This tornado outbreak took place just a little over 3 years after the largest October tornado outbreak for the state and the nation occurred on October 4, 1998, when 27 tornadoes hit parts of central and eastern Oklahoma.

Fast Facts

Information Sources

• NWS Event Chronology for the October 9, 2001 Tornado Outbreak

• Oklahoma Department of Emergency Management Situation Update web page for the October 9, 2001 Tornado Outbreak


• Storm Prediction Center Storm Report for October 9, 2001


• SPC Severe Weather Event Review for October 9, 2001


• NWS Norman Storm Data Report for October 2001


• Texas Tech University Wind Science and Engineering Research Center Report: Damage Documentation of Tornado of 9 October 2001 at Cordell, OK

Situation Report #1 October 11, 2001

Synopsis

Surface and Upper Level Features Associated with the October 9, 2001 Tornado Outbreak in Western Oklahoma

Written by Dan Miller, former Forecaster at NWS Norman, Oklahoma

A localized, but significant late-season tornado outbreak occurred in parts of west central and central Oklahoma during the late afternoon and evening hours on 9 October 2001. The large scale meteorological features and atmospheric conditions over much of the central and southern plains for this event were quite similar to what might be expected on a severe weather day during the spring months of the year. This emphasizes yet again that if the right atmospheric conditions are present, severe weather can and will occur regardless of the time of year.

By early evening on 9 October, a large scale mid and upper-level trough, which had strengthened significantly since early morning on the 9th, was located over the central Rockies with two smaller scale disturbances (short-wave troughs) embedded within the larger scale flow pattern, one extending from central Nebraska to Oklahoma, and another over the central Rockies.

At jet stream level, a speed maximum of 65 knots was located over Oklahoma and eastern Kansas. At 850 mb (roughly 5,000 feet above ground level), a strong low-level jet was located from Oklahoma northward into eastern Nebraska and western Iowa, with wind speeds in excess of 40 knots. Along the low-level jet axis, deep layer of rich moisture was present, with 850 mb dewpoint temperatures (a measure of the absolute moisture content of the air) in excess of 14 degrees Celsius over a large part of Texas and Oklahoma.

At the surface, the primary area of low pressure at 4 PM CDT was located over southern Nebraska, with a secondary low pressure center over South Dakota. A dry line extended from the low pressure center in Nebraska, through Kansas, along the Texas/Oklahoma border and southward to just west of San Angelo, Texas. A cold front extended from South Dakota to eastern Colorado, with a warm front extending eastward into Iowa from the surface low in Nebraska.

The surface thermal ridge (axis of warmest surface temperatures) was located just to the west of the dry line, where temperatures warmed into the upper 80s from the Texas panhandle northward into western Kansas. To the east of the dry line, surface dewpoints were in the mid 60s to lower 70s over a large part of central and western Oklahoma, with the surface moisture axis extending from near the Dallas/Fort Worth metroplex, to Lawton, to near Hutchinson, Kansas.

There were several smaller scale features at the surface which appeared to be very important for this event. Although not clearly evident in the surface pressure field as a true mesolow, the Oklahoma mesonet showed that a rather strong small scale cyclonic circulation developed along the Texas/Oklahoma border during the afternoon. Strong surface pressure falls greater than 5 millibars in 3 hours also developed over southwest Oklahoma during the late afternoon. In addition, a complex of thunderstorms had affected much of central and eastern Oklahoma during most of the day on October 9, and by mid afternoon, the outflow boundary from those storms was located from near Clinton, to Duncan, to Ardmore. In the vicinity of this outflow boundary, surface dewpoints increased into the lower 70s by around 4 PM.

The combination of these 3 small scale features resulted in rather strong east to southeast surface winds from 15 to 25 mph during the late afternoon across much of the southwest third of Oklahoma. As a result, atmospheric conditions over western Oklahoma were very favorable for the development of severe thunderstorms by mid-afternoon on October 9.

The atmosphere was very unstable with CAPE (Convective Available Potential Energy) values from 2500 to 3500 j/kg (joules per kilogram). The surface to 6 kilometer (roughly 18,000 feet above ground) wind shear was around 50 knots, which is generally strong enough to support supercell thunderstorms.

Given the strength of the instability and deep layer wind shear that was present, there were two other features of particular concern by late afternoon: 1) the presence of a nearly saturated and very unstable boundary layer airmass just east of the dry line where temperatures were in the mid 70s, with dewpoints from 70 to 72 and 2) very strong values of wind shear within the lowest 1 kilometer (roughly 3,000 feet) above ground. Surface to 1km storm relative helicity values were in excess of 400 j/kg for much of the late afternoon and evening across areas of Oklahoma along and south of Interstate 40, and west of Interstate 44, with peak surface to 1 km helicity values in excess of 600 j/kg observed just southwest of the Oklahoma City metro area just after sunset.

Not surprisingly, thunderstorms rapidly developed and intensified about 30 to 50 miles east of the surface dryline during the late afternoon. Most of these thunderstorms became supercells and produced numerous tornadoes as they moved eastward through areas of west central into central Oklahoma where the best combination of instability and wind shear was located.

Storm Data

Preliminary Storm Reports for 10/09/2001 Compiled by the Storm Prediction Center

LOCAL STORM REPORTS
NATIONAL WEATHER SERVICE NORMAN OK

SUMMARY REPORT OF LSRS ISSUED BY NWS NORMAN ON OCTOBER 9-10, 2001
 
TIME (CDT) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....
  
0220 PM    5 NW ERICK                OK   1.75 INCH HAIL           
10/09/01   BECKHAM                        AMATEUR RADIO REPORT       
  
0239 PM    5 WNW SAYRE               OK   TORNADO                  
10/09/01   BECKHAM                        AMATEUR RADIO REPORT.       
                                                                     
0247 PM    5 SE SWEETWATER           OK   TORNADO                  
10/09/01   BECKHAM                        SHERIFFS OFFICE REPORT.
                                                                   
0245 PM    6 W SAYRE                 OK   1.00 INCH HAIL           
10/09/01   BECKHAM                        REPORTED BY PUBLIC                           

0315 PM    1/2 E BERLIN              OK   TORNADO                  
10/09/01   ROGER MILLS                    BECKHAM CO EMERGENCY       

0323 PM    BERLIN                    OK   WIND DAMAGE. ROOF OFF MOBILE             
10/09/01   ROGER MILLS                    HOME. BECKHAM COUNTY EMERGENCY   

0400 PM    7 S BUTLER                OK   1.00 INCH HAIL           
10/09/01   CUSTER                         WASHITA NWR                

0420 PM    HERRING                   OK   1.00 INCH HAIL           
10/09/01   ROGER MILLS                    RPTD BY SHERIFFS OFFICE    

0425 PM    15 NNW ELK CITY           OK   1.00 INCH HAIL           
10/09/01   BECKHAM                        RPTD BY PUBLIC             

0445 PM    4 N FOSS                  OK   TORNADO                  
10/09/01   WASHITA                        RPTD BY MEDIA              

0445 PM    4 N FOSS                  OK   TORNADO                  
10/09/01   CUSTER                         RPTD BY MEDIA              

0450 PM    HOBART                    OK   1.00 INCH HAIL           
10/09/01   KIOWA                          AMATEUR RADIO REPORT       
  
0508 PM    CORDELL                   OK   TORNADO                  
10/09/01   WASHITA                        SEVERAL HOMES DAMAGED OR   
                                          DESTROYED.  SHERIFFS OFFICE
                                          REPORT.                    
  
0505 PM    HOBART                    OK   1.50 INCH HAIL           
10/09/01   KIOWA                          AMATEUR RADIO REPORT.      
  
0525 PM    HOBART                    OK   1.00 INCH HAIL           
10/09/01   KIOWA                          AMATEUR RADIO REPORT.      
                                                                     
  
0528 PM    GOTEBO                    OK   1.00 INCH HAIL           
10/09/01   KIOWA                          AMATEUR RADIO REPORT       
                                                                     
  
0530 PM    1 SW CUSTER CITY          OK   1.75 INCH HAIL           
10/09/01   CUSTER                         PUBLIC REPORT              
                                                                     
0539 PM    1 NE GOTEBO               OK   TORNADO                  
10/09/01   KIOWA                          AMATEUR RADIO REPORT.     
                                                                     
  
0542 PM    2 WSW MOUNTAIN VIEW       OK   TORNADO                  
10/09/01   KIOWA                          AMATEUR RADIO REPORT.      
                                                                     
0555 PM    9 S COWDEN                OK   TORNADO                  
10/09/01   WASHITA                        AMATEUR RADIO REPORT.      
                                                                     
  
0557 PM    3 SE WEATHERFORD          OK   TORNADO                  
10/09/01   CUSTER                         MEDIA REPORT.              
  
0700 PM    3 S ALBERT                OK   TORNADO                  
10/09/01   CADDO                          RPTD BY SPOTTER            
  
0720 PM    41/2 N GRACEMONT          OK   TORNADO                  
10/09/01   CADDO                          BINGER P.D. REPORT         
  
0734 PM    COGAR                     OK   1.00 INCH HAIL           
10/09/01   CADDO                          AMATEUR RADIO REPORT       
                                                                     
0740 PM    2 S MINCO                 OK   .88 INCH HAIL            
10/09/01   GRADY                          AMATEUR RADIO REPORT.      
  
0750 PM    2 W COGAR                 OK   2.00 INCH HAIL           
10/09/01   CADDO                                                     

0805 PM    UNION CITY                OK   1.00 INCH HAIL           
10/09/01   CANADIAN                       MUSTANG P.D. REPORT.       
  
0815 PM    2 W MINCO                 OK   1.00 INCH HAIL           
10/09/01   GRADY                          AMATEUR RADIO REPORT.      
  
0823 PM    1 W MINCO                 OK   1.75 INCH HAIL           
10/09/01   GRADY                          AMATEUR RADIO REPORT.      
  
0848 PM    S. OKLAHOMA CITY          OK   1.00 INCH HAIL           
10/09/01   CLEVELAND                      PUBLIC REPORT AT 134TH AND 
  
0910 PM    NEWCASTLE                 OK   .88 INCH HAIL            
10/09/01   MCCLAIN                        AMATEUR RADIO REPORT.      
  
0829 PM    NEWCASTLE                 OK   .75 INCH HAIL            
10/09/01   MCCLAIN                        AMATEUR RADIO REPORT       
  
0856 PM    MOORE                     OK   .75 INCH HAIL            
10/09/01   CLEVELAND                      SOONER ROAD AND SE 134TH.  
  
0925 PM    S. OKLAHOMA CITY          OK   .88 INCH HAIL            
10/09/01   CLEVELAND                      SW 134TH AND SANTA FE.     
  
0945 PM    TINKER AFB                OK   1.00 INCH HAIL           
10/09/01   OKLAHOMA                       AMATEUR RADIO REPORT.      

1025 PM    CHOCTAW                   OK   1.00 INCH HAIL           
10/09/01   OKLAHOMA                       MEDIA REPORT.              

1050 PM    4 N MIDWAY                OK   .75 INCH HAIL            
10/09/01   LINCOLN                        AMATEUR RADIO REPORT.      
  
1100 PM    HARRAH                    OK   .88 INCH HAIL            
10/09/01   OKLAHOMA                       REPORTED BY PD

Tornado Data

Maps & Graphics

Damage Path Maps

Radar Imagery

Twin Lakes, OK (KTLX) Radar Loop with Zoomed-in View of Western Oklahoma for October 9, 2001

Twin Lakes, OK (KTLX) Radar Loop for October 9, 2001

Frederick, OK (KFDR) Radar Loop for October 9, 2001

Vance AFB, OK (KVNX) Radar Loop for October 9, 2001

Satellite Imagery

Loop of Visible Satellite Images on October 9, 2001 with a Zoomed-in View of Southwestern Oklahoma

Loop of Visible Satellite Images on October 9, 2001 with a View of Western Oklahoma and Western North Texas

Storm Multimedia

Cordell, OK F3 Tornado

The following 8 images were taken by a Kiowa County Deputy, Doug Beamon, one mile north of Cordell, OK at ~5:30 PM CDT on 10/09/2001. He was located about two hundred yards away from the tornado as moved north-northeast and he was driving south into Cordell

These following two photos were taken by a resident of Cordell at ~5:10 PM CDT on 10/09/2001 as this F3 tornado approached the town from the southwest.

Damage Photos

Storm A Damage Photos

The following 26 photos were taken by former NWS Norman General Forecaster David Floyd during his survey of the Storm A tornado damage paths on October 10, 2001.

Damage Photos along the October 9, 2001 "Berlin, OK" F1 Tornado Path

Damage Photos along the October 9, 2001 Elk City, OK F3 Tornado Path

Storm D and Storm E Damage Photos

The following 23 photos were taken by Storm Prediction Center Forecaster Roger Edwards during his survey of the Storm D and Storm E tornado damage paths on October 10, 2001. Roger surveyed damage paths in southwestern Oklahoma near the towns of Gotebo, Mountain View, and Binger.

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