2013 El Reno Tornado

[Coach McGuirk]

It was measured with winds of 290+ MPH yet it only had EF-3 damage.  Is the new EF formula flawed?  A 200+ MPH tornado in the middle of nowhere can be classified as an EF-1 because it didn't do any damage. 

[CheeselandSkies]

The rating was correct based on the damage that was available to survey.

The underrating of many tornadoes based on lack of available DIs is a flaw common to both the original Fujita and EF-scales. That said, the 2013 El Reno tornado did not leave behind much of the contextual evidence common to exceptionally violent tornadoes such as total stripping/scouring of vegetation, wind rowing of debris, and extreme mangling of vehicles. The TWISTEX Cobalt was probably the worst-damaged vehicle I've seen pictures of from that tornado, and even it was not as bad as some vehicles I've seen photographed that had been through confirmed E/F5 tornadoes.

[billgwx]

In this day and age, one would think reliable measured or estimated winds would supplement or trump DI's.

[Coach McGuirk]

On 5/22/2018 at 9:41 PM, CheeselandSkies said:

The rating was correct based on the damage that was available to survey.

The underrating of many tornadoes based on lack of available DIs is a flaw common to both the original Fujita and EF-scales. That said, the 2013 El Reno tornado did not leave behind much of the contextual evidence common to exceptionally violent tornadoes such as total stripping/scouring of vegetation, wind rowing of debris, and extreme mangling of vehicles. The TWISTEX Cobalt was probably the worst-damaged vehicle I've seen pictures of from that tornado, and even it was not as bad as some vehicles I've seen photographed that had been through confirmed E/F5 tornadoes.

[Rjay]

On 5/23/2018 at 11:40 AM, billgwx said:

In this day and age, one would think reliable measured or estimated winds would supplement or trump DI's.

Agree Bill.

 

Make sure you visit the NYC subforum this winter or if any good severe events are imminent.  We miss you.   

[David Reimer]

On 5/22/2018 at 8:15 PM, Coach McGuirk said:

It was measured with winds of 290+ MPH yet it only had EF-3 damage.  Is the new EF formula flawed?  A 200+ MPH tornado in the middle of nowhere can be classified as an EF-1 because it didn't do any damage. 

No scale will ever be perfect. The wind measurements for a couple tornadoes were taken into account in the original surveys done by the TOP and OUN offices for Bennington v1 and the 2013 El Reno (respectively). It was a blanket-NOAA mandate from the higher-ups that reversed those decisions. It was made policy that only damage indicators (DIs) could be used to rate tornadoes. The EF-scale is a damage-based rating scale. In that sense, the scale is doing what its designed. 

On 5/22/2018 at 8:41 PM, CheeselandSkies said:

The rating was correct based on the damage that was available to survey.

The underrating of many tornadoes based on lack of available DIs is a flaw common to both the original Fujita and EF-scales. That said, the 2013 El Reno tornado did not leave behind much of the contextual evidence common to exceptionally violent tornadoes such as total stripping/scouring of vegetation, wind rowing of debris, and extreme mangling of vehicles. The TWISTEX Cobalt was probably the worst-damaged vehicle I've seen pictures of from that tornado, and even it was not as bad as some vehicles I've seen photographed that had been through confirmed E/F5 tornadoes.

1

Very good explanation!

Anyway, there are plenty of folks unhappy that in-situ observations from mobile radars and mesonets (looking at you OK Mesonet) are not able to be used to rate tornadoes. A committee is underway containing the best from various fields to create a new scale. Tim Marshall is among those on that committee. Last I heard, which was back in February, it sounds like the new scale should be ready around 2022. I know they're looking to update several of the DIs as they've found some flaws in the EF-scale DI numbers, plus new DIs they didn't think of back in the 2000s. 

I've come to accept the current EF-scale as a 'damage scale' versus a tornado intensity scale. It does that job fairly well. Do violent tornadoes get rated EF0-EF2/EF-U? Absolutely! The Tescott, KS (2018/05/01) tornado was rated an EF-3 by the NWS Topeka with the wording in their original PNS saying "The longer-track, violent tornado...". Another example is the Dimmitt, TX wedge (2017/04/14) where multiple significant tornadoes occurred, but only one produced ratable damage (EF-3). I was present for both of the aforementioned days and can confirm both featured rather pissed-off tornadoes. 

Here is a part of the PNS (Public Information Statement) for the Dimmitt, Texas tornado event from April 14, 2017 (NWS LUB). While the lack of DIs precluded the rating of all but one of the tornadoes, the NWS LUB acknowledges the tornadoes that did occur likely were rather potent. Even on the rated-tornado (an EF-3), they hint the tornado was likely stronger/capable of producing higher DIs during its peak intensity. 

Quote

 

Numerous brief tornadoes occurred as the storm moved toward the City of Dimmitt. The absence of damage indicators across rural western Castro County precluded determination of any path or intensity estimates. Streaming video suggested that at least 5 brief tornadoes formed across western Castro county with some exhibiting multi-vortex characteristics.

The main tornado with this event exhibited a path of approximately 4.5 miles on a north-northeasterly track. The most significant damage observed was located about three miles west of Dimmitt where a metal systems building was completely destroyed. The remnants were displaced several hundred feet northwest of the original site. This corresponds with a maximum damage rating of EF-3. Several nearby homes received up to EF-2 damage. Elsewhere along the path, a lack of damage indicators made classification difficult though numerous power poles and center pivots were damaged. Streaming video of the event at its peak suggested a large wedge type tornado with satellite vortices.

 

 

Something introduced in the last couple of years has been the EF-U rating. Not all offices have used it, but OUN certainly seems to since 2016. They'll assign that rating to tornadoes that don't produce damage but were confirmed visually by spotters/chasers/law enforcement/granny with a camera phone. EF-U stands for Unknown. I still chuckle when I hear EF-U mentioned