Further thoughts about the TIR rating system......

     As I have been working with this new system to rate tornados, I came across a small dilemma; one I should have anticipated. When we went from the F system to the EF system, wind speeds were adjusted. The whole reason for the switch to the EF system had to do with studies that showed that it took far less wind speed to cause a certain degree of damage. In order to keep apples to apples, they made the EF system where the damage apparent in an F4 was the same as the damage done by an EF4, although the wind speed estimate was different. For my TIR system to work, I need an accurate wind speed, even if estimated. The problem I am running into is that the wind speeds from F scale rated tornados haven't been readjusted.
     The 1999 OKC tornado isn't a problem as that tornado was measured with a Doppler Radar and that is acceptable in my TIR rating. However, as I was attempting to get a TIR rating on the Hallum tornado, I realized that they didn't have a definitive wind speed rating. All they said was that it was an F-4, and that it was only in small pockets. Most of the damage was F-3 or less. In this instance, I would be inclined to say this tornado was on the lower end of the F-4 scale and I would "guesstimate" a wind speed rating. However, when you look at the wind speeds of an F-4 tornado, you notice that the F-4 range is now into the current EF-5 range. That makes the Hallum tornado appear stronger than many EF-5 tornados when you attempt to TIR rate it using F scale wind estimates.
     What I may have to do is just convert from F to EF scale, then "guesstimate" the wind speed rating since damage between F and EF scales are supposed to be relatively the same. If the Hallum tornado had minor F4 damage, then I assume it is safe to say that it had minor EF4 damage, and therefore we can make an estimated wind speed rating based upon this. Until someone goes through and reassesses these old F scale damage surveys and converts them to EF, it seems to be my only option unless there is other information available, like a Doppler reading.