Update (Noon 7/29): Two tornadoes confirmed from July 27th; First Iron County Tornado in 40 Years

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Four Decades: It's been 40 years since a tornado has been confirmed and officially documented in Iron County, Wisconsin. Ashland County last saw a confirmed tornado in 1998.

Survey Update (8:35 AM 7/29): The survey team has confirmed two tornado tracks from July 27th. Remember that these results are preliminary and more details will be added once we have had time to completely review the information gathered on the damage survey. The damage survey continues today, primarily in Ashland and Bayfield counties.

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE DULUTH MN
830 AM CDT THU JUL 29 2010

...PRELIMINARY RESULTS FROM STORM SURVEY IN ASHLAND/IRON CO...

THE STORM SURVEY TEAM SURVEYED PART OF THE DAMAGE IN ASHLAND AND
IRON COUNTIES YESTERDAY...JULY 28TH. THEY HAVE CONFIRMED TWO
TORNADOES THAT OCCURRED ON THE EVENING OF JULY 27TH:

  1.  ON THE TURTLE FLAMBEAU FLOWAGE NEAR SPRINGSTEAD LANDING
      IN IRON COUNTY

      THE TORNADO DAMAGE IN THIS AREA WAS EMBEDDED WITHIN A BROAD
      SWATH OF WIND DAMAGE. THE DAMAGE CAUSED BY THE TORNADO WAS
      PRIMARILY IN THE SPRINGSTEAD LANDING AREA OF THE TURTLE
      FLAMBEAU FLOWAGE...WHERE FLOWAGE ROAD EXTENDS NORTH ON A
      SMALL PENINSULA. THE MAJORITY OF THE DAMAGE IN THE FLOWAGE WAS
      DUE TO EXTREME STRAIGHT-LINE THUNDERSTORM WINDS.

  2.  JUST NORTH OF HIGHWAY F ALONG RODDIS LINE RD
      IN FAR EASTERN ASHLAND COUNTY

      LIKE THE OTHER TORNADO...THIS ONE WAS EMBEDDED WITHIN A BROAD
      SWATH OF WIND DAMAGE.

MORE SPECIFIC DETAILS AND EF RATINGS FOR EACH TORNADO WILL BE
RELEASED ONCE THE SURVEY TEAM RETURNS AND HAS HAD TIME TO THOROUGHLY
REVIEW THE INFORMATION COLLECTED. THE TEAM WILL ASSESS DAMAGE IN THE
REMAINDER OF ASHLAND COUNTY...AND INTO BAYFIELD COUNTY TODAY.

Storm Surveys: The NWS Duluth will be concluding a storm survey in Bayfield, Ashland, and Iron Counties today. We received many reports of damage in these areas and radar signatures indicated the possibility of tornadoes. An unconfirmed report of a tornado was received from the Morse area in Ashland County. The survey team will determine whether or not the damage in the area was caused by non-tornadic thunderstorm winds or by tornado(es).

We Could Use Pictures and Reports: If you have any pictures or reports from the severe weather event, feel free to email us by clicking here or give us a call at 1-218-729-6794

Fast Facts

2 tornadoes confirmed so far

First tornado in Iron County since July 7, 1970, and only the 4th tornado in the county since 1950.

First tornado in Ashland County since May 12, 1998, and only the 8th tornado in the county since 1950.

14 warnings issued by NWS Duluth - 4 Tornado Warnings and 10 Severe Thunderstorm Warnings

30 severe weather reports received by the NWS Duluth. We also received 17 additional non-severe reports.

Up to baseball size hail reported in Bayfield County, where wind driven hail caused a substantial amount of damage, particularly in the Delta township.

Storm Damage Photos


Morse, WI in Ashland County. Photos courtesy of Paul Ostrum from the Chequamegon-Nicolet National Forest

Data and Images

Warning Polygons Issued by NWS Duluth on July 27th (blue: severe tstm warning, red: tornado warning)


Regional Radar Loop (click for loop)	Regional Visible Satellite Loop (click for loop)

Here are some graphics from the SPC Mesoanalysis page, which is based on a RUC computer model analysis of the atmosphere at the indicated times. SBCAPE is surface based CAPE, a measure of instability in the atmosphere. Eff. Shear is effective wind shear which measures the amount of deep layer wind shear that a thunderstorm may experience. 30 to 40 knots or more is typically favorable for supercell thunderstorms - powerful rotating storms. Eff. SRH stands for effective storm relative helicity in which higher values tend to favor thunderstorms with rotating updrafts. STP stands for Significant Tornado Parameter which combines a number of different variables in the atmosphere to gauge the potential for strong tornadoes (EF2 or stronger); values of 1 or more are considered "favorable".

Time (CDT)	SBCAPE	Eff. Shear	Eff. SRH	STP
1 PM	GIF	GIF	GIF	GIF
4 PM	GIF	GIF	GIF	GIF
7 PM	GIF	GIF	GIF	GIF
10 PM	GIF	GIF	GIF	GIF

Below is a radar image from 5:31 PM CDT from Bayfield County. The large spike of low reflectivities extending southeast from the storm is what is referred to as a "three body scatter spike". These spikes are commonly indicators of a thunderstorm producing severe hail. We received reports of golfball size hail from these areas in Bayfield County. To the right of the radar image is a graphic explaining briefly how the "three body scatter spike" works.


5:31 PM CDT Radar Image - Bayfield County	Graphic Explaining Three-Body Scatter Spike

Storm Reports

Here is a collection of storm reports that we received at our office. Above is a national storm reports map from the Storm Prediction Center.

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0420 PM     TSTM WND DMG     2 N AITKIN              46.56N 93.71W
07/27/2010                   AITKIN             MN   TRAINED SPOTTER

            TREES DOWN NEAR AIKTIN WITH REPORTED WIND GUST OF 50 MPH.


0458 PM     TSTM WND DMG     MAPLE                   46.59N 91.72W
07/27/2010                   DOUGLAS            WI   LAW ENFORCEMENT

            SEVERAL POWER LINES DOWN.

0500 PM     LIGHTNING        9 SW DULUTH             46.69N 92.25W
07/27/2010                   ST. LOUIS          MN   NEWSPAPER

            *** 1 INJ *** A TEENAGE BOY WAS STRUCK BY LIGHTNING WHILE
            JOGGING ON SKYLINE PARKWAY NEAR SPIRIT MOUNTAIN.

0500 PM     HAIL             S PROCTOR               46.74N 92.23W
07/27/2010  M1.50 INCH       ST. LOUIS          MN   TRAINED SPOTTER

0500 PM     TSTM WND DMG     1 N BLUEBERRY           46.59N 91.67W
07/27/2010                   DOUGLAS            WI   TRAINED SPOTTER

            3 LARGE TREES DOWN

0520 PM     HAIL             2 SE IRON RIVER         46.54N 91.38W
07/27/2010  M1.00 INCH       BAYFIELD           WI   TRAINED SPOTTER

0520 PM     TSTM WND DMG     5 SE IRON RIVER         46.51N 91.33W
07/27/2010                   BAYFIELD           WI   TRAINED SPOTTER

            TREES DOWN ON RV TRAPPING CAMPER AT TWIN BEAR CAMPGROUND.

0530 PM     HAIL             8 SE IRON RIVER         46.48N 91.29W
07/27/2010  E1.75 INCH       BAYFIELD           WI   PUBLIC

            HAIL UP TO THE SIZE OF GOLF BALLS AT SCENIC DRIVE RESORT.
            ALSO...IN NEARBY AREAS ALONG HIGHWAY H...SOME TREES BLOWN
            DOWN AND A FEW SNAPPED OFF INCLUDING RED PINES AND OAKS.

0530 PM     HAIL             6 SW INO                46.47N 91.27W
07/27/2010  E1.75 INCH       BAYFIELD           WI   LAW ENFORCEMENT

            HAIL OF QUARTER TO GOLFBALL SIZE DENTED THREE VEHICLES
            AND CRACKED THE WINDSHIELD OF A POLICE CAR AS IT WAS
            DRIVEN BY EXTREMELY STRONG WINDS. TREE DAMAGE ALSO NOTED.

0535 PM     HAIL             3 S INO                 46.49N 91.18W
07/27/2010  E2.75 INCH       BAYFIELD           WI   EMERGENCY MNGR

            A COMBINATION OF SEVERE WIND AND HAIL CAUSING DAMAGE.
            WHEAT AND CORN FIELDS DESTROYED ALONG COUNTY HIGHWAY E.
            ALSO...SHINGLES BLOWN FROM A ROOF AND SIDING DAMAGE TO A
            HOUSE. BARN NEARLY COLLAPSED. REPORTS OF SPIKY GOLFBALL
            TO BASEBALL SIZE HAIL. HIGHWAY DEPT HAD TO SCRAPE ROADWAY
            CLEAR OF SEVERAL INCHES OF WET LEAVES THAT GOT STRIPPED
            FROM TREES BY WIND DRIVEN HAIL.

0545 PM     TSTM WND DMG     BENOIT                  46.50N 91.08W
07/27/2010                   BAYFIELD           WI   EMERGENCY MNGR

            ROOF BLOWN OFF OF A BARN.

0548 PM     HAIL             MASON                   46.44N 91.06W
07/27/2010  E1.00 INCH       BAYFIELD           WI   POST OFFICE

            ALSO A FEW TREES BLOWN DOWN IN THE AREA.

0600 PM     TSTM WND GST     11 WNW DRUMMOND         46.39N 91.47W
07/27/2010  E47.00 MPH       BAYFIELD           WI   MESONET

            41 MPH GUST MEASURED AT BARNES RAWS. THIS WOULD BE
            APPROXIMATELY 47 MPH WHEN ADJUSTED FOR A 10M WIND /RAWS
            MEASUREMENTS TAKEN AT 6M/.

0602 PM     HAIL             4 W MARENGO             46.42N 90.90W
07/27/2010  E1.75 INCH       ASHLAND            WI   PUBLIC

            LEAVES SHREDDED OFF TREES IN THE AREA. RELAYED BY A STORM
            SPOTTER.

0619 PM     HAIL             HIGH BRIDGE             46.39N 90.74W
07/27/2010  M1.75 INCH       ASHLAND            WI   AMATEUR RADIO

0621 PM     TORNADO          MORSE                   46.22N 90.63W
07/27/2010                   ASHLAND            WI   PUBLIC

            UNCONFIRMED PUBLIC REPORT OF A TORNADO RELAYED THROUGH
            COPPER FALLS STATE PARK.

0622 PM     HAIL             2 N MELLEN              46.35N 90.66W
07/27/2010  M1.00 INCH       ASHLAND            WI   TRAINED SPOTTER

0626 PM     HAIL             2 N MELLEN              46.35N 90.66W
07/27/2010  M1.50 INCH       ASHLAND            WI   TRAINED SPOTTER

0628 PM     TSTM WND DMG     1 N GLIDDEN             46.15N 90.58W
07/27/2010                   ASHLAND            WI   LAW ENFORCEMENT

            TREE DOWN

0634 PM     TSTM WND DMG     6 W TREGO               45.90N 91.95W
07/27/2010                   WASHBURN           WI   TRAINED SPOTTER

            SEVERAL TREES DOWN 6 INCHES IN DIAMETER

0650 PM     HAIL             10 NNE HAYWARD          46.14N 91.40W
07/27/2010  M1.75 INCH       SAWYER             WI   TRAINED SPOTTER

0653 PM     TSTM WND DMG     INO                     46.53N 91.18W
07/27/2010                   BAYFIELD           WI   AMATEUR RADIO

            2 FOOT DIAMETER TREE SNAPPED ABOVE GROUND.

0705 PM     HEAVY RAIN       ASKOV                   46.19N 92.78W
07/27/2010  M1.71 INCH       PINE               MN   TRAINED SPOTTER

            FELL IN THE LAST 2 HOURS

0710 PM     TSTM WND GST     MINONG                  46.10N 91.82W
07/27/2010  E49.00 MPH       WASHBURN           WI   MESONET

            43MPH GUST MEASURED AT MINONG RAWS. APPROX 49MPH WHEN
            ADJUSTED FROM 6M RAWS HEIGHT TO 10M STANDARD ANEMOMETER
            HEIGHT.

0711 PM     HEAVY RAIN       1 SW HINCKLEY           46.00N 92.95W
07/27/2010  M2.00 INCH       PINE               MN   TRAINED SPOTTER

            FELL IN THE LAST 50 MINUTES

0722 PM     HEAVY RAIN       MINONG                  46.10N 91.82W
07/27/2010  M2.13 INCH       WASHBURN           WI   MESONET

            FELL IN THE LAST HOUR. MINONG RAWS.

0727 PM     TSTM WND DMG     TURTLE FLAMBEAU FLOWAGE 46.08N 90.18W
07/27/2010                   IRON               MN   LAW ENFORCEMENT

            NUMEROUS TREES DOWN. REPORTED BY IRON COUNTY SHERRIF
            OFFICE.

0728 PM     TSTM WND DMG     2 N STONE LAKE          45.87N 91.54W
07/27/2010                   WASHBURN           WI   UTILITY COMPANY

            POWER LINES DOWN ON COUNTY HWY A

0730 PM     TSTM WND DMG     1 N MERCER              46.18N 90.06W
07/27/2010                   IRON               WI   AMATEUR RADIO

            NUMEROUS TREES DOWN

0730 PM     TSTM WND DMG     MERCER                  46.17N 90.06W
07/27/2010                   IRON               WI   AMATEUR RADIO

            NUMEROUS TREES DOWN ALONG MURRAY LANDING RD. POWER LINES
            ALSO DOWN. ROADS BLOCKED IN AREA.

0730 PM     TSTM WND DMG     STONE LAKE              45.85N 91.54W
07/27/2010                   SAWYER             WI   LAW ENFORCEMENT

            LARGE TREE DOWN ON BOUTEN ROAD

0730 PM     TSTM WND DMG     2 NE SPOONER            45.85N 91.86W
07/27/2010                   WASHBURN           WI   LAW ENFORCEMENT

            LARGE TREE LIMB ON CABIN

0740 PM     TSTM WND DMG     TURTLE FLAMBEAU FLOWAGE 46.08N 90.18W
07/27/2010                   IRON               MN   EMERGENCY MNGR

            *** 6 INJ *** PRELIMINARY REPORT. RESCUES IN PROGRESS ON
            THE ISLANDS.

0747 PM     HEAVY RAIN       UPSON                   46.37N 90.41W
07/27/2010  M2.85 INCH       IRON               WI   TRAINED SPOTTER

            FELL THIS EVENING.

0748 PM     HEAVY RAIN       6 W TREGO               45.90N 91.95W
07/27/2010  M1.50 INCH       WASHBURN           WI   TRAINED SPOTTER

            FELL FROM 710 PM TO 740 PM

0749 PM     NON-TSTM WND GST 1 NW PORT WING          46.78N 91.40W
07/27/2010  E40.00 MPH       BAYFIELD           WI   OTHER FEDERAL

            35 KT WIND GUST MEASURED AT PORT WING MARINE OBSERVATION
            SITE...PNGW3.

0752 PM     TSTM WND DMG     BIRCHWOOD               45.66N 91.55W
07/27/2010                   WASHBURN           WI   LAW ENFORCEMENT

            LARGE PINE TREE FELL ON CABIN AND MADE A HHOLE IN THE
            ROOF.

0756 PM     HEAVY RAIN       HAYWARD                 46.01N 91.48W
07/27/2010  M2.60 INCH       SAWYER             WI   ASOS

            FELL FROM 656 PM TO 756 PM

0800 PM     TSTM WND DMG     PARK FALLS              45.93N 90.45W
07/27/2010                   PRICE              WI   LAW ENFORCEMENT

            TIME APPROXIMATE. SEVERAL TREES DOWN. REPORTED BY PRICE
            COUNTY DISPATCH

0806 PM     TSTM WND DMG     2 NNW RADISSON          45.80N 91.23W
07/27/2010                   SAWYER             WI   TRAINED SPOTTER

            LARGE TREE DOWN BLOCKING HIGHWAY 70 AND 27. BLINDING
            RAIN.

0823 PM     HEAVY RAIN       HAYWARD                 46.01N 91.48W
07/27/2010  M2.68 INCH       SAWYER             WI   MESONET

            2.00 INCHES FELL IN THE LAST HOUR.

0904 PM     HEAVY RAIN       GILE                    46.43N 90.23W
07/27/2010  M3.10 INCH       IRON               WI   TRAINED SPOTTER

            WITH THUNDERSTORMS

1000 PM     HEAVY RAIN       UPSON                   46.37N 90.41W
07/27/2010  M3.15 INCH       IRON               WI   CO-OP OBSERVER

            STORM TOTAL RAINFALL.

1000 PM     HEAVY RAIN       4 S BRUNO               46.22N 92.67W
07/27/2010  M2.60 INCH       PINE               MN   CO-OP OBSERVER

            STORM TOTAL RAINFALL.

1000 PM     HEAVY RAIN       11 WNW DRUMMOND         46.39N 91.47W
07/27/2010  M2.10 INCH       BAYFIELD           WI   MESONET

            1.36 INCHES BETWEEN 7PM AND 8PM AT BARNES RAWS.

1000 PM     HEAVY RAIN       BRUNO                   46.28N 92.67W
07/27/2010  M2.21 INCH       PINE               MN   CO-OP OBSERVER

            STORM TOTAL RAINFALL.

1100 PM     HEAVY RAIN       MINONG                  46.10N 91.82W
07/27/2010  M2.57 INCH       WASHBURN           WI   MESONET

            MEASURED AT THE MINONG RAWS. 2.13 INCHES BETWEEN 7PM AND
            8PM.

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Update (Noon 7/29): Two tornadoes confirmed from July 27th; First Iron County Tornado in 40 Years