Severe WX April 11th-13th, 2020 Severe Weather Threat

[Shakespeare2016]

It's one of those cases where we'd have probably had back to back F5s if this were the 1990s, but now construction quality is scrutinized so closely I'm sure any EF4 damage points are going to be few and far between. Makes it hard to compare events.

That is true. These two tornadoes were at least comparable to tornadoes like Hesston, Gossell, and maybe even Andover and Bridge Creek. That is to name a few.

 

[buckeye05]

Ok so i'm going through the points that have been added to the Damage Assessment Toolkit right now for the main Bassfield/Soso tornado, and what I'm seeing is pretty interesting, if not a bit exciting. JAN seems to be taking a liberal approach with this one, ala pre late-2014. If there's any EF5 damage along the path, it looks like they will rate it as such. There is definitely a chance!

Also, happy to hear the first Bassfield tornado from the lead cell has also been upgraded. That slabbed, anchor-bolted house rated EF3 was not sitting well with me, along with many others I'm sure.

 

[Equus]

Yeah that rating seems appropriate, glad they bumped it. First multiple violent day since Pilger in June 2014 and tied with last year's violent totals already, before we even finish April

 

[Kory]

Ok so i'm going through the points that have been added to the Damage Assessment Toolkit right now for the main Bassfield/Soso tornado, and what I'm seeing is pretty interesting, if not a bit exciting. JAN seems to be taking a liberal approach with this one, ala pre late-2014. If there's any EF5 damage along the path, it looks like they will rate it as such. There is definitely a chance!

Also, happy to hear the first Bassfield tornado from the lead cell has also been upgraded. That slabbed, anchor-bolted house rated EF3 was not sitting well with me, along with many others I'm sure.

Rumors are swirling they will.

 

[Shakespeare2016]

Ok so i'm going through the points that have been added to the Damage Assessment Toolkit right now for the main Bassfield/Soso tornado, and what I'm seeing is pretty interesting, if not a bit exciting. JAN seems to be taking a liberal approach with this one, ala pre late-2014. If there's any EF5 damage along the path, it looks like they will rate it as such. There is definitely a chance!

Also, happy to hear the first Bassfield tornado from the lead cell has also been upgraded. That slabbed, anchor-bolted house rated EF3 was not sitting well with me, along with many others I'm sure.
That tornado was way up there on the scale along with the bigger monster EF4 tornado.

 

[andyhb]

This is what happens when you put a large supercell in a classic environment for strong-violent tornadoes.

 

[buckeye05]

Rumors are swirling they will.

Ooooh elaborate! DM me if need be.

 

[Equus]

The fact that JAN slapped an EF4+ on it before even really looking at it definitely grabbed my attention. Usually if they believed we would end up at EF4, they slap on "EF3+". Am wondering about the tornado behind it too, with an 83 mile long mile wide path I wonder if they find any pockets above EF3.

 

[Equus]

We're on page 100... wow

 

[Shakespeare2016]

The fact that JAN slapped an EF4+ on it before even really looking at it definitely grabbed my attention. Usually if they believed we would end up at EF4, they slap on "EF3+". Am wondering about the tornado behind it too, with an 83 mile long mile wide path I wonder if they find any pockets above EF3.

They actually have not put a wind speed on the 2 mile-wide monster EF4 tornado.

 

[Shakespeare2016]

We're on page 100... wow

This outbreak was definitely not to the extent of the outbreak of 4/27/11 but there are more pages on this thread than that one.

 

[buckeye05]

Also, interesting to note, the first EF4 from the lead supercell is the first E/F4 in the LIX area since 1983, and the first EF4 in the LIX area since the implementation of the Enhanced Fujita Scale. A historic event!

 

[vanni9283]

They actually have not put a wind speed on the 2 mile-wide monster EF4 tornado.

That's because it's still preliminary.

 

[vanni9283]

All comes down to construction quality at the end of the day, now matter how insane the contextual damage is. I’d say it was almost certainly an EF5, but whether it hit anything well-built enough to prove this 100% remains to be seen.

What would have an impact on construction quality other than anchor bolting?

 

[buckeye05]

Quality of wall studding is a big one, along with if the bolts are closely or widely spaced. Quality of roof attachment is another, along with quality of construction materials. How old the structure is another. I’ve seen downgrades due to factors such as termite rot in wood framing with older structures.

 

[vanni9283]

We might not know for a few days what the final rating will be. At least this NWS is doing their due diligence on this one. That's for sure.

 

[Kory]

 

[Equus]

If you look closely at the official EF scale DIs, the absolute maximum that an average frame home can be assigned is 200mph (high EF4) without using the slider to bump it toward upper bound - which requires 'superior' construction above the building code. The problem with that is not only the rarity of 'superior' homes, but that a 'superior' home has to be hit at PEAK intensity, and be located somewhere that the WFO doesn't assume failure mode was due to other non 'superior' homes nearby disintegrating and pelting it with debris. AND, of course, being in a WFO that will even acknowledge it. Given all that, you can see why EF5s are so rare, especially when frame homes are about the only major DIs to go off of.

 

[buckeye05]

If you look closely at the official EF scale DIs, the absolute maximum that an average frame home can be assigned is 200mph (high EF4) without using the slider to bump it toward upper bound - which requires 'superior' construction above the building code. The problem with that is not only the rarity of 'superior' homes, but that a 'superior' home has to be hit at PEAK intensity, and be located somewhere that the WFO doesn't assume failure mode was due to other non 'superior' homes nearby disintegrating and pelting it with debris. AND, of course, being in a WFO that will even acknowledge it. Given all that, you can see why EF5s are so rare, especially when frame homes are about the only major DIs to go off of.

From what I’ve heard, there is a specific reason it gets left at 200 MPH. This was done intentionally by those who created the EF Scale, so that the only factor differentiating EF4 and EF5 damage, is contextual damage. Actually a great idea, but the problem is, there is no official guide to interpreting contextual evidence. In fact, some WFOs disregard contextual evidence altogether.

In my opinion, there should be a supplementary guide on how to interpret contextual damage in association with established DIs. It would clear up so many inconsistencies.

 

[andyhb]

This damage is NE of Soso. That tornado maintained higher end intensity for a long time.