Assigning EF Scale Ratings Based on Radar Indicated Wind Speeds

[Natester]

That would be a complete crock if they downgraded that one, it likely should've been an EF5 without radar evidence given the damage around the Cactus Rig 117 site.

 

Well, I just heard that the El Reno EF5 from 2011 was downgraded too.

[tornadotony]

Well, I just heard that the El Reno EF5 from 2011 was downgraded too.

Source?  Link?

[Natester]

Source?  Link?

 

Caleb Chevalier ‏@TriStateChasing8h

@severestudios I'd imagine this will raise questions about Rozel, Bennington, and Clearwater from this year. El Reno from 2011 too.

 

^^^^^^^

[tornadotony]

 

Caleb Chevalier ‏@TriStateChasing8h

@severestudios I'd imagine this will raise questions about Rozel, Bennington, and Clearwater from this year. El Reno from 2011 too.

 

^^^^^^^

 

How in the world do you get that they're downgrading it based off of that statement?  There are people on this board who can attest that the 2011 tornado was right on the EF4/5 fence and the radar simply pushed it solidly over.  That rating is not changing.

[Natester]

How in the world do you get that they're downgrading it based off of that statement?  There are people on this board who can attest that the 2011 tornado was right on the EF4/5 fence and the radar simply pushed it solidly over.  That rating is not changing.

 

Whoops!  I misunderstood that tweet!  I guess I was wrong afterall. XD

 

*goes off and eats his shoe now*

[LocoAko]

Whoops!  I misunderstood that tweet!  I guess I was wrong afterall. XD

 

*goes off and eats his shoe now*

 

Yeah, I think they only meant that it will have questions raised about it since it is one of the prominent tornadoes that was rated via radar. That tornado was much more on the EF4/EF5 fence (compared to an EF3 to EF5 jump) so I'd expect them to let that one "slide" so to speak, although who knows at this point what HQ will decide. 

[thewxmann]

Well, I just heard that the El Reno EF5 from 2011 was downgraded too.

 

Wow, you almost gave me a heart attack there. That would be an unbelievable atrocity.

[Ed Lizard]

Again, an inherent inconsistency between the EF scale and SS scale.  Katrina and Rita would only have been Cat 3s, using the logic of the EF scale.  Ike would have been the stronger hurricane, since it hit the Turks and Caicos as a Cat 4.

 

I don't see the sense in disregarding scientific evidence in the name of consistency.

[TropicalAnalystwx13]

That would be a complete crock if they downgraded that one, it likely should've been an EF5 without radar evidence given the damage around the Cactus Rig 117 site.

The NWS office in Norman rated damage along the tornado's path as EF4. It was only upgraded to EF5 given radar data.

 

Rick Smith said on Twitter that the width of the El Reno tornado (this one, not the 2011 one) was decreased with the help of radar.

[Ensō]

The NWS office in Norman rated damage along the tornado's path as EF4. It was only upgraded to EF5 given radar data.

 

Rick Smith said on Twitter that the width of the El Reno tornado (this one, not the 2011 one) was decreased with the help of radar.

 

That's not what Andy's referring to. He's referring to the fact that there were some incredible instances of damage, especially at and near Cactus 117, that many (including me) feel should have warranted EF5 regardless of radar measurements -- some examples being the rolling of the 1.9-million pound rig itself, the apparent throwing of an oil tanker nearly one mile, almost unprecedented vegetation damage, etc.

[Buckeye05]

The NWS office in Norman rated damage along the tornado's path as EF4. It was only upgraded to EF5 given radar data.

 

Rick Smith said on Twitter that the width of the El Reno tornado (this one, not the 2011 one) was decreased with the help of radar.

I don't know about that. In Ortega's speech on the May 24th outbreak at AMS 2012, he mentioned the movement/rolling of the oil rig as EF5 damage. I think that is the main determining factor for why the 2011 event stays, and the 2013 event is getting dropped. In the 2011 event, the damage was consistent with that of an EF5 tornado, in 2013 it simply wasn't.

 

I mean just look. See the red control panel in the foreground? That is where the derrick itself originated. It weighed 1.9 million pounds, and was rolled end over end four times. Think about that. I don't see how winds below 200 MPH could do such a thing. 

 

 

The 2011 event also produced other EF5 hallmarks, such as extreme granulation of debris, and total removal of all surface vegetation in some areas. 

[TropicalAnalystwx13]

 

I don't know about that. In Ortega's speech on the May 24th outbreak at AMS 2012, he mentioned the movement/rolling of the oil rig as EF5 damage. I think that is the main determining factor for why the 2011 event stays, and the 2013 event is getting dropped. In the 2011 event, the damage was consistent with that of an EF5 tornado, in 2013 it simply wasn't.

 

I mean just look. See the red control panel in the foreground? That is where the derrick itself originated. It weighed 1.9 million pounds, and was rolled end over end four times. Think about that. I don't see how winds below 200 MPH could do such a thing. 

 

 

The 2011 event also produced other EF5 hallmarks, such as extreme granulation of debris, and total removal of all surface vegetation in some areas. 

 

 

 

That's not what Andy's referring to. He's referring to the fact that there were some incredible instances of damage, especially at and near Cactus 117, that many (including me) feel should have warranted EF5 regardless of radar measurements -- some examples being the rolling of the 1.9-million pound rig itself, the apparent throwing of an oil tanker nearly one mile, almost unprecedented vegetation damage, etc.

Oh yeah, I'm definitely not debating it wasn't an EF5. I was just stating that the NWS Norman rated the damage the tornado caused as EF4 (again, don't agree with that).

[blackjack123]

I tend to wonder if this recent El Reno tornado was capable of doing EF5 damage to a skyscraper and not capable of it at the surface. I also wondered if the strongest suction vortices somehow failed to make contact with the ground. If 295mph winds had touched the field where DOW had clocked it there would have been extreme ground scouring. Anyone have any thoughts on this.

[tornadotony]

I tend to wonder if this recent El Reno tornado was capable of doing EF5 damage to a skyscraper and not capable of it at the surface. I also wondered if the strongest suction vortices somehow failed to make contact with the ground. If 295mph winds had touched the field where DOW had clocked it there would have been extreme ground scouring. Anyone have any thoughts on this.

It is a little curious that there was a lack of ground scouring, but I don't think that precludes a lack of EF5 winds at the ground level in this case.  A lot of the ground scouring effects seen are due to the debris load carried by a tornado.  For instance, I observed small patches of ground pocked and scoured up by pieces of a aluminum grain bin while surveying a low-end EF2 tornado in Newton County, IN on 25 May 2011.  IMO, the three reasons for observing scouring are 1) increased intensity, 2) increased debris load, and 3) favorable soil/growth in soil.  On top of (2) lacking in the El Reno tornado, most of the pictures I've seen have shown some sort of wheat or other tall grass in the fields, which I imagine would make scouring the dirt more difficult.  Beyond that, it's pure speculation as to the intensity profile inside this particular tornado.  Our sample size is extremely small, but every indication published thus far indicates a peak in tornado winds within about 50 m of ground level.  In fact, Kosiba and Wurman's latest publication on the tornado boundary layer suggests that the peak may even be lower than that, perhaps by a factor of 10.

[TropicalAnalystwx13]

Rozel was left at EF4 based on damage to a house (which is strange because the first damage survey they did said the damage was EF2).

 

Bennington, KS was downgraded to EF3 though NWS Topeka says they strongest suspect it was a violent EF4.

[thewxmann]

Clearwater, KS was left at an EF2, with the justification that DOW measured EF3 winds but minimal damage was observed.

 

Also, and not surprisingly, the 295 mph readings were found in small subvortices, which did not hit any structures.