L.B. LaForce Posted April 10, 2011 Share Posted April 10, 2011 Don't know who Derek is... http://www.weather.c...ht-on-cam-20304 That would actually be Darrin, a.k.a. Darin Brunin here is his video, you can see Andy and Dick back up near the beginning. Link to comment Share on other sites More sharing options...
thewxmann Posted April 10, 2011 Share Posted April 10, 2011 Information on Mapleton: PUBLIC INFORMATION STATEMENTNATIONAL WEATHER SERVICE OMAHA/VALLEY NE 308 PM CDT SUN APR 10 2011 ...TORNADO DAMAGE IN MONONA COUNTY IOWA INCLUDING MAPLETON... THIS IS A PRELIMINARY MESSAGE. ADDITIONAL DETAILS MAY BE PROVIDED LATER. A SURVEY TEAM DID A DAMAGE ASSESSMENT OF THE TORNADO THAT MOVED ACROSS PARTS OF MONONA COUNTY IOWA SATURDAY EVENING APRIL 9 2011. THIS INCLUDED THE TOWN OF MAPLETON. SO FAR...A PATH LENGTH OF AROUND 3.5 MILES HAS BEEN DETERMINED. THE MAXIMUM WIDTH OF THE TORNADO WAS 0.75 MILES. THE WORST DAMAGE WAS NOTED TO BE IN THE LOWER END OF THE EF3 CATEGORY. MONONA COUNTY EMERGENCY MANAGEMENT ESTIMATED 12 TO 14 INJURIES...THE WORST OF WHICH WAS A BROKEN LEG. EF3 WIND DAMAGE IS CAUSED BY WINDS ESTIMATED AT 136 TO 165 MPH. http://www.crh.noaa....=66512&source=0 Link to comment Share on other sites More sharing options...
thewxmann Posted April 11, 2011 Share Posted April 11, 2011 4 EF2s and 2 EF3s in Sac and Pocahontas counties. 1 EF1 in Kossuth County. Note that one of the tornadoes was 2-3 mi wide O__O (Tornado No 1 in Pocahontas Co). Other than that, almost all the rest of the tornadoes in the Sac-Pocahontas counties were 1/2 - 1 mile wide, and all but one in the two counties had path lengths around 8-16 miles long. Beastly. Divided up into different colors to differentiate between the three counties: PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE DES MOINES IA 837 PM CDT SUN APR 10 2011 ...PRELIMINARY DAMAGE SURVEY RESULTS FOR SAC...POCAHONTAS...AND KOSSUTH COUNTIES... THE STORM SURVEY INVESTIGATION IS STILL ONGOING AND SUBJECT TO FURTHER COORDINATION WITH LOCAL EMERGENCY MANAGEMENT AGENCIES. THIS SURVEY WILL BE UPDATED ON MONDAY WITH ADDITIONAL INFORMATION. ...SURVEY FOR SAC COUNTY, IOWA... THE FOLLOWING IS A PRELIMINARY ASSESSMENT FOR THE DAMAGE THAT OCCURRED OVER SAC COUNTY ON APRIL 10, 2011. * EVENT DATE: APRIL 10, 2011 * TORNADO NUMBER 1 * ESTIMATED START TIME: UNKNOWN * EVENT TYPE: (EF2) TORNADO * EVENT LOCATION: TORNADO BEGAN 6 NNE ODEBOLT AND ENDED 1.5 NE EARLY * PEAK WIND: 132 MPH * AVERAGE PATH WIDTH: 1/2 MILE WIDE * PATH LENGTH: 9 MILES LONG * INJURIES: UNKNOWN * FATALITIES: NONE KNOWN * DISCUSSION/DAMAGE: MULTIPLE HOMES DAMAGED * TORNADO NUMBER 2 * ESTIMATED START TIME: UNKNOWN * EVENT TYPE: (EF3) TORNADO * EVENT LOCATION: TORNADO BEGAN 1 N ODEBOLT AND ENDED 5 NW EARLY * PEAK WIND: 140 MPH * AVERAGE PATH WIDTH: 1 MILE WIDE * PATH LENGTH: 11 MILES LONG * INJURIES: UNKNOWN * FATALITIES: NONE KNOWN * DISCUSSION/DAMAGE: MULTIPLE HOMES DAMAGED OR DESTROYED * TORNADO NUMBER 3 * ESTIMATED START TIME: UNKNOWN * EVENT TYPE: (EF2) TORNADO * EVENT LOCATION: TORNADO BEGAN 1.5 WSW NEMAHA AND ENDED APPROXIMATELY 4.5 S NEWELL * PEAK WIND: 125 MPH * AVERAGE PATH WIDTH: 1/2 MILE WIDE * PATH LENGTH: 8 MILES LONG FOR THIS SEGMENT...ANOTHER TEAM IS SURVEYING A PORTION OF THE SAME STORM THROUGH ANOTHER AREA. * INJURIES: UNKNOWN * FATALITIES: NONE KNOWN * DISCUSSION/DAMAGE: HIGH TENSION WIRES DOWN...MULTIPLE HOMES DAMAGED OR DESTROYED...HOG OUTBUILDINGS DOWN. * TORNADO NUMBER 4 * ESTIMATED START TIME: UNKNOWN * EVENT TYPE: (EF2) TORNADO * EVENT LOCATION: TORNADO BEGAN 2.5 NW NEMAHA AND ENDED ABOUT 4 NW OF NEMAHA. * PEAK WIND: 125 MPH * AVERAGE PATH WIDTH: 1/2 MILE WIDE * PATH LENGTH: 12 MILES LONG * INJURIES: UNKNOWN * FATALITIES: NONE KNOWN * DISCUSSION/DAMAGE: MULTIPLE HOMES DAMAGED OR DESTROYED...OUTBUILDINGS DOWN ...SURVEY FOR POCAHONTAS COUNTY, IOWA... THE FOLLOWING IS A PRELIMINARY ASSESSMENT FOR THE DAMAGE THAT OCCURRED OVER POCAHONTAS COUNTY ON APRIL 10, 2011. * EVENT DATE: APRIL 10, 2011 * TORNADO NUMBER 1 * ESTIMATED START TIME: UNKNOWN * EVENT TYPE: (EF2) TORNADO * EVENT LOCATION: TORNADO BEGAN 4 SW OF VARINA AND CROSSED THE COUNTY LINE AND ENDED 2 NNW OF WARE * PEAK WIND: 125 MPH * AVERAGE PATH WIDTH: 2-3 MILES WIDE * PATH LENGTH: 16 MILES LONG * INJURIES: UNKNOWN * FATALITIES: NONE KNOWN * DISCUSSION/DAMAGE: IN VARINA A CHURCH GYMNASIUM COLLAPSED. AN OLDER HOUSE COLLAPSED AND WAS MOVED OFF OF ITS FOUNDATION. * TORNADO NUMBER 2 * ESTIMATED START TIME: UNKNOWN * EVENT TYPE: (EF3) TORNADO * EVENT LOCATION: TORNADO 5 SOUTHWEST OF WARE AND TRAVELED ABOUT 3 MILES TO ABOUT 2 S OF WARE AND MERGED INTO THE PREVIOUS TRACK. * PEAK WIND: 165 MPH * AVERAGE PATH WIDTH: 300-400 YARDS * PATH LENGTH: 2-3 MILES LONG * INJURIES: UNKNOWN * FATALITIES: NONE KNOWN * DISCUSSION/DAMAGE: A MANUFACTURED WICK HOME WAS COMPLETELY REMOVED. A COMBINE WAS BLOWN INTO A FIELD AND ROLLED OVER SEVERAL TIMES. ...SURVEY FOR KOSSUTH COUNTY, IOWA... THE FOLLOWING IS A PRELIMINARY ASSESSMENT FOR THE DAMAGE THAT OCCURRED OVER KOSSUTH COUNTY ON APRIL 10, 2011. * EVENT DATE: APRIL 10, 2011 * TORNADO NUMBER 1 * ESTIMATED START TIME: UNKNOWN * EVENT TYPE: (EF1) TORNADO * EVENT LOCATION: TORNADO BEGAN 3 WNW OF ST. JOSEPH AND ENDED 2 MILES NORTHWEST OF ST. JOSEPH. * PEAK WIND: 90 MPH * AVERAGE PATH WIDTH: 200 YARDS * PATH LENGTH: 1.5 MILES * INJURIES: UNKNOWN * FATALITIES: NONE KNOWN * DISCUSSION/DAMAGE: A HOG CONFINEMENT WAS FLATTENED AT THE BEGINNING OF THE TORNADO NEAR 100TH ST AND 100TH. ABOUT ONE HALF MILE EAST OF THAT...LARGE WINDOWS WERE BLOWN OUT OF A HOUSE AND HALF OF A SHED WAS COLLAPSED. && http://www.crh.noaa....=66515&source=0 Link to comment Share on other sites More sharing options...
thewxmann Posted April 11, 2011 Share Posted April 11, 2011 Three more tornadoes in FSD's area. So far count across the OAX-DMX-FSD NWSFO's is 2 EF1's, 6 EF2's, 3 EF3's. http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=fsd&storyid=66507&source=0 ...TORNADO NEAR NEWELL IOWA RATED EF2...* EVENT LOCATION: Tornado began 2 miles northwest of Nemaha and ended approximately at the Buena Vista, Sac, Pocahontas, Calhoun county line. * PEAK WIND: 125 MPH * AVERAGE PATH WIDTH: 1/2 mile wide * PATH LENGTH: 12 miles long. * DISCUSSION/DAMAGE: Multiple homes and outbuildings damaged or destroyed. Philip Schumacher – Science and Operations Office National Weather Service Sioux Falls, South Dakota PUBLIC INFORMATION STATEMENTNATIONAL WEATHER SERVICE SIOUX FALLS SD 138 PM CDT SUN APR 10 2011 ...TORNADO NEAR ARTHUR IOWA RATED EF2... A SUPERCELL DEVELOPED OVER NORTHEAST NEBRASKA ON THE EVENING OF APRIL 9 AND PRODUCED SEVERAL TORNADOES OVER NORTHWESTERN IOWA. ONE TORNADO DEVELOPED SOUTHWEST OF ARTHUR IOWA IN SOUTHERN IDA COUNTY BETWEEN 8:15 AND 8:20 PM CDT. THE MOST SIGNIFICANT DAMAGE WAS DONE TO A FARM THAT WAS LOCATED 2 MILES WEST OF ARTHUR WHERE SEVERAL BUILDINGS WERE DAMAGED AND THERE WAS DAMAGE TO TREES AND POWER LINES. A NATIONAL WEATHER SERVICE ONSITE SURVEY HAS RATED THE TORNADO AS EF2. THE TORNADO DEVELOPED SOUTHWEST OF ARTHUR AND STRENGTHEN AS IT CROSSED HIGHWAY 175 TWO MILES WEST OF ARTHUR WHERE IT DID EF2 DAMAGE TO A FARMSTEAD. THE TORNADO WAS AT ITS WIDEST IN THIS AREA...HAVING A WIDTH OF ONE-QUARTER MILE. THE TORNADO CONTINUED TO MOVE NORTHEAST AND WEAKENED AS IT MOVED NORTH OF ARTHUR. THE TORNADO HAD A PATH LENGTH OF APPROXIMATELY 4 MILES. A WEAKER TORNADO DEVELOPED SOUTHWEST OF GALVA IOWA AROUND 840 PM CDT. THIS TORNADO WAS RATED EF1 WHEN IT DID DAMAGE TO AN ETHANOL PLANT 2 MILES SOUTH OF GALVA NEAR HIGHWAY 20. OTHER STORM SURVEYS ARE BEING PERFORMED ACROSS NORTHWESTERN IOWA BY NATIONAL WEATHER SERVICE SURVEY TEAMS FROM DES MOINES IOWA AND OMAHA NEBRASKA. THIS INCLUDES A SURVEY OF A TORNADO WHICH DID DAMAGE NEAR NEWELL IOWA IN BUENA VISTA COUNTY. ADDITIONAL INFORMATION ON THESE TORNADOES...INCLUDING SPECIFIC TRACK INFORMATION...WILL BE POSTED TO OUR WEB SITE AT WEATHER.GOV/SIOUXFALLS EARLY NEXT WEEK. $ Link to comment Share on other sites More sharing options...
blackjack123 Posted April 11, 2011 Share Posted April 11, 2011 4 EF2s and 2 EF3s in Sac and Pocahontas counties. 1 EF1 in Kossuth County. Note that one of the tornadoes was 2-3 mi wide O__O (Tornado No 1 in Pocahontas Co). Other than that, almost all the rest of the tornadoes in the Sac-Pocahontas counties were 1/2 - 1 mile wide, and all but one in the two counties had path lengths around 8-16 miles long. Beastly. Divided up into different colors to differentiate between the three counties: http://www.crh.noaa....=66515&source=0 2-3 miles wide seems like an error but maybe it was. One tornado sounds like it might as well be rated EF4 since the wind speed is only 1 mph away from it. Link to comment Share on other sites More sharing options...
Fred Gossage Posted April 11, 2011 Share Posted April 11, 2011 2-3 miles wide seems like an error but maybe it was. One tornado sounds like it might as well be rated EF4 since the wind speed is only 1 mph away from it. There have been tornadoes wider than 2 miles wide. The current record is being held by the 2.5 mile wide F4 that hit Hallam, Nebraska on May 22, 2004. It sounds like this tornado might have broken that record. Link to comment Share on other sites More sharing options...
blackjack123 Posted April 11, 2011 Share Posted April 11, 2011 There have been tornadoes wider than 2 miles wide. The current record is being held by the 2.5 mile wide F4 that hit Hallam, Nebraska on May 22, 2004. It sounds like this tornado might have broken that record. You would think a tornado that is 2-3 miles wide would be an EF4 or EF5. I guess it did not impact enough structures to be rated higher than EF2. Link to comment Share on other sites More sharing options...
Hoosier Posted April 11, 2011 Share Posted April 11, 2011 You would think a tornado that is 2-3 miles wide would be an EF4 or EF5. I guess it did not impact enough structures to be rated higher than EF2. Or it might not have been that strong. There's somewhat of a relationship between size and intensity but you can find a lot of examples that go against it. Link to comment Share on other sites More sharing options...
blackjack123 Posted April 11, 2011 Share Posted April 11, 2011 Or it might not have been that strong. There's somewhat of a relationship between size and intensity but you can find a lot of examples that go against it. Yeah, there seems a good correlation between size and intensity but it does not necessarily since its a damage scale. A tornado more than a mile-wide might only do F1(EF1) or F2(EF2) damage on either the F-scale or EF-scale, but a rope tornado less than 100 yds wide might do F4(EF4) or F5(EF5). Good examples of violent rope/cone tornadoes would be like Tracy, MN, Pampa, TX, Oakfield, WI, and Elie, MB. Large tornadoes that were fairly weak were like Happy, TX. and the one during the May 10th outbreak from last year that was 1.4 miles-wide. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted April 11, 2011 Share Posted April 11, 2011 Not going to lie, at first we had no idea this was even a tornado (there was a satellite rope tornado to the Southwest that we were concentrating on) and I looked to the Northwest and started asking my right hand man Brad if that was a wedge on the ground. The more we watched it, the more we were convinced. Had no idea it was 2-3 miles wide though. Absolutely amazing. We saw so many tornadoes last night that we literally lost count. Amazing two day chase - I'll never chase in Wisconsin again though, awful terrain, awful data, awful road network. Link to comment Share on other sites More sharing options...
BowMeHunter Posted April 11, 2011 Share Posted April 11, 2011 Good don't come back.. Enough idiots from the south on the roads up here. Link to comment Share on other sites More sharing options...
Chicago Storm Posted April 11, 2011 Share Posted April 11, 2011 So Chi Storm, myself and 2 others rode the Mapleton supercell from its infancy (first radar echoes) in eastern Nebraska all the way to Pocahantas, IA this evening. What an amazing storm. It occluded and re-strengthened over a half dozen times, and at a couple points had several mesos all rotating around each other. Just before it hit Mapleton, it had occluded and formed this massive cyclonic gyre (essentially one big meso) with an extremely long and impressive inflow tail. We rode to Mapleton to get ahead of it, and stopped under the BP gas station awning there to take shelter from one of the many hail shafts this thing spit out along the way, which were extremely prominent and very noticeable. It was truly awesome to see it dump a massive load of hail and see it fall to the ground in a matter of seconds. About the time we got to the station, we had another hail shaft threatening the vehicle, so we hunkered down. Right at about this time, it cycled, and produced a new meso within a couple of minutes. Chi Storm caught a snapshot of the meso at the time the tornado was developing. We hopped in the vehicle immediately and sped away from the station, as it had literally developed and moved towards us from just a few hundred yards away. Luckily we got to an escape route right down the street about 20-30 seconds before it did. It then proceeded to chase us out of town and eventually grow into a big tornado. The shot Chi Storm took above was looking back down the road, and though you can't tell from the picture, it was heading right for us at a pretty good clip. We got beat up a bit by the FFD, but luckily was able to ride the edge and not take serious damage to the vehicle. After hunkering down near Battle Creek, we caught up to it in time to see it dropping another tornado. Later, we got some great lightning and structure video. The storm structure tonight was simply awesome. Since csnavywx handled the disco, here are a few pictures/video to go with it... Link to comment Share on other sites More sharing options...
Srain Posted April 11, 2011 Share Posted April 11, 2011 Good don't come back.. Enough idiots from the south on the roads up here. lol Link to comment Share on other sites More sharing options...
OceanStWx Posted April 11, 2011 Share Posted April 11, 2011 Or it might not have been that strong. There's somewhat of a relationship between size and intensity but you can find a lot of examples that go against it. Sounds like a missed out on a good event (or two, but I'm just finishing reading this thread) this weekend. Looking back at some of the posts, I saw a few related to this. The main difficulty is that it is a damage scale and not a direct measurement. For that reason if a tornado doesn't hit any structures of significance there is no way to tell approximately how strong the winds were. I think back to the survey I did on 6/6/10 of the Magnolia, IL tornado from the day before. I have a feeling it may have been a low end EF3, but it was cycling as it entered town. Therefore no structures showed higher than EF2 damage, and outside of town there was nothing to hit besides open fields. Our team decided we would rate it right up to the top of the EF2 scale in that case (135 mph not 136 mph). You can also run into the problem of poorly built or maintained structures. Those can be completely destroyed at a much lower wind speed than otherwise expected. This is why the EF-Scale has upper and lower bounds. Another possibility, mainly in regards to the 1 mph short of EF4 discussion, is that only one structure had damage indicative of higher strength. Sometimes that isn't enough to jump to the next rating. Was that construction poor, was it damaged by other debris and not the tornadic winds, etc? Sometimes secondary confirmation is more appropriate. Also, if damage was truly in the violent (EF4/EF5) range, experts are called in so they can examine the construction quality down the individual anchor points and hurricane clips. And there have also been some good posts about how the more destructive tornadoes are generally also quite large, but several contradictory examples were brought up. Some of the teams that made up VORTEX2 have data that almost looks as if whole mesos have descended to the ground, giving the appearance of a very wide damage path (which is wind damage that rotated cyclonically), so where do you end the tornado damage swath can sometimes be tricky. Just trying to maybe shed some light onto the subject for those that are less familiar with it, but that's why damage surveys are so interesting, so many variables involved. Link to comment Share on other sites More sharing options...
hm8 Posted April 11, 2011 Share Posted April 11, 2011 And there have also been some good posts about how the more destructive tornadoes are generally also quite large, but several contradictory examples were brought up. Some of the teams that made up VORTEX2 have data that almost looks as if whole mesos have descended to the ground, giving the appearance of a very wide damage path (which is wind damage that rotated cyclonically), so where do you end the tornado damage swath can sometimes be tricky. Just trying to maybe shed some light onto the subject for those that are less familiar with it, but that's why damage surveys are so interesting, so many variables involved. Forgive me for my ignorance, but whats the difference between a meso coming all the way to the ground and a two mile-wide tornado? ....Couldn't all tornado damage be described as "wind damage that rotated cyclonically" (save for updrafts in the tornado, i suppose). Link to comment Share on other sites More sharing options...
thewxmann Posted April 11, 2011 Share Posted April 11, 2011 NWS DMX has put out a page on the tornadoes, which includes prelim tracks and damage pictures. You may check it out here: http://www.crh.noaa....=66541&source=0 Information from the page indicates that the towns of Early and Varina took direct hits, with extensive damage in both (some rivaling the Mapleton damage IMO). They were lucky the tornado(es) were not stronger when they hit. One of the tornadoes has been upgraded to an EF3, and in my previous count i had counted one of the tornadoes twice. Additionally I think DMX merged the tracks of two of the tornadoes. Thus the revised total is across the three CWA's affected on the 9th is: 2 EF1 3 EF2 4 EF3 9 total tornadoes. Link to comment Share on other sites More sharing options...
OceanStWx Posted April 11, 2011 Share Posted April 11, 2011 Forgive me for my ignorance, but whats the difference between a meso coming all the way to the ground and a two mile-wide tornado? ....Couldn't all tornado damage be described as "wind damage that rotated cyclonically" (save for updrafts in the tornado, i suppose). That was my point. While a meso on the ground may only have wind damage of EF0 strength, the tornadic circulation within the meso could be much higher. I believe, but don't quote me on it, there have been observed damage swaths near 5 miles wide associated with a meso with an embedded tornado track inside it. The idea being that the larger meso would rotate more slowly, with a tornadic swath of much more intense and concentrated damage embedded within it. But I can imagine it would be very difficult to differentiate where one would begin and the other would end. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted April 12, 2011 Share Posted April 12, 2011 That was my point. While a meso on the ground may only have wind damage of EF0 strength, the tornadic circulation within the meso could be much higher. I believe, but don't quote me on it, there have been observed damage swaths near 5 miles wide associated with a meso with an embedded tornado track inside it. The idea being that the larger meso would rotate more slowly, with a tornadic swath of much more intense and concentrated damage embedded within it. But I can imagine it would be very difficult to differentiate where one would begin and the other would end. This appeared to be the case as we were on this tornado and while the whole meso appeared to be literally sitting on the ground, we would see a "elephant trunk/stove pipe tornado" emerge from the meso/small rope tornado emerge from the meso, etc. It did this for quite a while, while at the same time, the whole back drop looked liked a massive wedge. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted April 18, 2011 Share Posted April 18, 2011 NWS Des Moines has confirmed a third tornado in Pocahontas County on the 9th. Event date: April 9, 2011. Event time: to be determined. Intensity rating: EF0. Event location: began 3.5 miles W of Pocahontas and ended 3 NW miles Pocahontas. Peak wind: 100 mph. Peak path width: 250 yds. Path length: 2.5 mile. Injuries: unknown. Fatalities: none known. Also updated information page http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=dmx&storyid=66541&source=0 Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 2, 2011 Share Posted May 2, 2011 Updated... 12 confirmed tornadoes in the DMX CWA on the 9th... http://www.crh.noaa....=66541&source=0 For the 9th(DMX/OAX/FSD)... EF-0: 1 EF-1: 6 (Two of which were a cyclonic/anti-cyclonic pair) EF-2: 4 EF-3: 3 (One of which was on the ground for about an hour with a max width of 1.5 miles) EF-3+: 1 -------------- 15 Link to comment Share on other sites More sharing options...
blackjack123 Posted May 3, 2011 Share Posted May 3, 2011 Pocahontas tornado was upgraded to EF4. Link to comment Share on other sites More sharing options...
thewxmann Posted May 3, 2011 Share Posted May 3, 2011 And this is probably why: http://www.crh.noaa.gov/images/dmx/StormSurveys/2011/20110410/TorD/AerialPhoto.JPG Link to comment Share on other sites More sharing options...
blackjack123 Posted May 3, 2011 Share Posted May 3, 2011 And this is probably why: http://www.crh.noaa....AerialPhoto.JPG I saw those damage photos a few weeks ago and yes, that is very impressive. Link to comment Share on other sites More sharing options...
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