I know this won’t appease the folks trying to farm reclaimed duck habitat, but Brad Edwards says Des Moines is less than a half inch above average on precip for the year. YMMV.
***Official 2024 Weather Thread***
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If the Minden to Manila ‘nader was tagged an EF4, the swath of destruction in Greenfield is nowhere close. That said, bad is bad.
That's not how it works though.
There's a good video interview out there with Tim Marshall, that explains all this much better. But he gave a version of it at his talk in 2023 at the Central Iowa NWA Doppler Radar and Severe Storms Conference, and has kindly let me use some of his PowerPoint deck for presentations to groups now.
He's a forensic meteorologist/engineer. He's been responsible for developing and updating the damage indicators with the EF-scale, and some in progress updates.
You can't just "eyeball" it. Shoddy construction, improperly installed, missing, old, etc etc can really make you vulnerable to much lower windspeeds.
"All walls gone," which is the quick and dirty explanation of EF-4, can actually occurring in a low-end EF-3 depending on construction.
Check out the lower bound values here on the single family residence damage indicators.
"Swab swept clean" can occur with estimated top-end EF-3 winds. You can't get an accurate EF rating solely from drone views.
Long story short, you can't just eyeball it and get an accurate rating from a drone view.
Might be easy to pick out a bunch of 9s, or even a couple 10s, but now the real work begins to put together an accurate estimate. So you get a preliminary EF3 on first pass since that is the lower bound. Further evidence may change that.
DIs for other stuff are here
Might be easy to pick out a bunch of 9s, or even a couple 10s, but now the real work begins to put together an accurate estimate. So you get a preliminary EF3 on first pass since that is the lower bound. Further evidence may change that.
DIs for other stuff are here
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not sure why people even care what it was rated. lives lost, lives ruined, homes destroyed, etc. really doesn't matter what it was rated.
Found a photo from 1982 in our yard tonight that we are pretty confident came from Greenfield. We live in Ames.
If there's an earthquake with lives lost, does the Richter number not matter?
I don't think anyone is downplaying the loss of property and lives. The biggest eye opener for me, as a dog lover, is seeing that impact and the number of lost pets. Aheinz is staying busy trying to help.
Having an indicator of size immediately like with a Richter scale is useful when reporting about the immediate impact. Having a scale that you may not know the impact for days after doesn’t really do much good other than talking about it over coffee.
It would be much more useful to develop an indicator based on wind speed and elevation to be able to give immediate indicators of strength and impact. Maybe this is asking too much for the radar technology that we have available? Cause what we saw with the multiple funnel clouds seemed a different beast than some of the smaller tornados that we’ve seen this season. Yet there’s not really a method to describe the size of them in the moment.
But why does it matter how fast the rating comes out?
Knowing whether it's an EF3 or EF5 isn't going to change anything that has already happened.
I agree, but I I could also see insurance companies that are already facing financial pressure leverage a payout system that is influenced by a damage rating: "We aren't going to cover your house to the same extent as your neighbors due to your construction methods or not being built to our updated standards....blah blah blah....because you weren't built to handle an EF2 and they were", or some such justification
I have the general path. I was hoping to see drone footage of the path between Cambridge & Colo to see what proximity it had to us.
The rating is really only important for historical/statistical purposes. I am not a huge fan of the EF scale. Yes, NWS personnel are trained and can bring in other experts to help, but they are not civil/construction engineers. So depending on availability, an inexperienced survey crew might not have a very accurate rating. But mostly, the severity or strength of the tornado is tied to what it hits. And oftentimes it is nothing but open fields/dirt. Or it's a 220 mph monster but only hits poorly constructed buildings thus stays EF3 or EF4 when in reality, it may have been an EF5 had it hit the rare structure that qualifies as well-built.
I think many tornadoes are underrated in intensity because of it.
I think many tornadoes are underrated in intensity because of it.
Which is why is important to remember that the EF-scale is not a wind-measurement scale.
The rating is on the damage, and not the tornado itself, directly speaking at least.
As far as using radar for ratings go, radar winds aloft are not that well correlated to what is happening at the surface. Severe Thunderstorm Warning verifications are all the further you have to look on that point.
Even the DOW measurement from Greenfield that set the internet on fire was still 144 feet in the air, and it was parked right outside of town! Then it's what fraction of 1% of all tornadoes have a DOW right on top of them?
Radar is sampling such an infinitesimally small percentage of tornadoes at anything close to approximating surface wind speed that it would add a whole new mess and layer of inconsistency to everything, so it's not a magic wand either.
Per that, it was less than a half mile from us, but that is a generalized, hand drawn image. I saw a video from my hygienist today and it shows the view from her house toward a treeline; the tornado was just on the far side of the trees. Using Google earth, at the point it was 0.45 miles from our front door, and passed to the east of us (but I'm not sure exactly how far over).
Basically, I think we dodged a bullet.
Edit: thank you for tracking that down for me!
The tornado started across the street from our house in Johnston. We were very fortunate we only lost a tree and fences. I was stupidly monitoring the weather from my deck when it touched down. I thought I was smarter than the weather, but it turns out you can’t track the potential path of a tornado when it first drops down a football field away from you.
Just heard the state insurance commissioner on the news talking about insurers leaving the state because the weather events the last couple years made it unprofitable to remain here. He also stated that some companies were giving discounts to those who's structures met certain criteria, which I was alluding could happen. They'd be protected from lawsuits if it were stated in your policy what standards need to be met and what premiums would be for different compliance to their standards would be offered. The rating of an actual tornado would be immaterial but the damage done by an event would be reflected by the building code parameters at certain premium levels thus accomplishing the same end. We all know that discounted premiums is a polite way to say you are all going to pay but we'll charge less if you are more bulletproof than the next guy.
The Elie, Manitoba tornado was never wide yet was still rated an F5.
