EF scale question and the classification of landspouts

[Ethan Schisler]

Landspout Tornadoes June 9th, 2019

www.weather.gov

On June 9, 2019 several landspout tornadoes formed over Northeast Iowa near Cedar Rapids. NWS Quad Cities has listed these as EF0 tornadoes with max winds of 50 mph. However I'm under the impression that EF0 starts at 65 mph, so does anyone have any speculation as to how a tornado can be an EF0 with estimated winds below 65 mph?

Mods: I'm not sure whether this belongs in introductory or advanced weather. Feel free to move it to the correct section if need be.

 

[Quincy Vagell]

I think it varies from office to office with NWS. I've seen some CWAs list a tornado as EF? if there was little/no damage, but I've also seen other EF0 listings for tornadoes that had winds under 65 mph or winds that were not listed, probably due to a lack of damage, as would be expected in many landspout cases.

For climo/historical purposes, it's more of a grey area. I'm not sure if EF? gets converted to EF0 or what happens to tornadoes that were reported to have had maximum winds under 65 mph. Perhaps, by default, tornadoes like these get lumped into EF0 for statistics, even if they might have not had winds reach 65 mph in an official summary.

 

[Jesse Risley]

Landspout Tornadoes June 9th, 2019

www.weather.gov

On June 9, 2019 several landspout tornadoes formed over Northeast Iowa near Cedar Rapids. NWS Quad Cities has listed these as EF0 tornadoes with max winds of 50 mph. However I'm under the impression that EF0 starts at 65 mph, so does anyone have any speculation as to how a tornado can be an EF0 with estimated winds below 65 mph?

Mods: I'm not sure whether this belongs in introductory or advanced weather. Feel free to move it to the correct section if need be.

They classified those as weak landspout tornadoes with "non severe winds" where "no damage was observed" and the only evidence was via photos and videos. I'm assuming the fact that they considered them to have "non severe winds" explains the estimated wind speed rating, but that might be a better question for Andy or one of those local mets to answer.

There is an official document that explains some of the nuances behind the EF-Scale's original proposal, with some notations that the original Fujita Scale did go down to 40 mph.
EF Scale Proposal