Tornado Just Before Striking Hallam, Nebraska (5-22-04)

[Jeff Snyder]

From what we saw, there were two long-track tornadoes... The Hallam tornado started from the last few images of Marc's, which are similar to what I have. I could be wrong, but that's how I see it.

Does anyone have complete tornado track map from Omaha? The only one I've found was for the Hallam tornado, though I thought I remember the prelim damage assessment stating a couple more tornadoes from the same storm earlier (a brief one in Thayer co. I thought, along with another long-track one)...?

 

[Shane Adams]

This topic is currently being discussed at great length in the chatroom......

 

[Larry J. Kosch]

Feedback from SPC

Hello,

I sent a feedback letter to the SPC about their entry in the local storm reports pertaining to the Hallam NE tornado on May 22, 2004. In the LSR log, it said " Sevral houses destroyed...major damage reported." I sent a feedback letter to them to ask them about the vague entry about the Hallam tornado. This is what I sent them:

Dear Sirs,
I was checking the following web site,
http://spc.noaa.gov/climo/torn/2004deadlytorn.html, and I found out to my surprise how the Hallam NE tornado was reported. Quote \" Sevral houses destroyed...major damage reported.\" That's quite an under statement. Nearly 90-95 percent of the homes and buildings in that village was heavily damaged. Not to mention how wide the storm damage track (2 1/2 mile wide, a record) was. I think the detail line should be updated to indicate the extensive damage and storm track width.
I'm a member of a group, StormTrack, and we discuss storm damage reports, such as yours, extensively in our forums. This type of under reporting does not diminish the devastating effects of a tornado on a small village like Hallam. Please correct this oversight before negative public opinion about storm reports is raised in our forums. Thanks.

Larry J. Kosch

This is the response I got back from Roger Edwards, a SPC Met specializing in tornadoes and other severe convection:

Larry,
I appreciate your feedback on this. In principle I agree. Our rough logs, however, are built automatically from the local storm reports (LSRs) sent to us by the warning offices; and we don't have the staffing to update them for every report. That's the commentary which was in the LSR. The final Storm Data logs, which unlike the SPC report log are *not* preliminary, will be more detailed.
Here is the NWS Omaha page on the event:
http://www.crh.noaa.gov/oax/archive/hallam/hallam.htm

If you have any more concerns or questions about the Hallam event, please contact Brian Smith of the NWS office on Valley NE. I'm copying
this reply to Brian also.

Roger Edwards
Meteorologist Storm Prediction Center

I hope this will add new information to your knowledge about the Hallam tornado. Thanks. 8)

 

[mrobinson]

Roger saw some of the damage from that tornado when he was out chasing in Nebraska this year.

 

[Thomas Loades]

From looking at the High Plains Climate Center path map, I’m inclined to think that there may have been two tornadoes involved — but my “second tornado†is in a different location to Blake’s. Perhaps there were three.

Anyway, the way the damage path decreases in width rapidly to the NE of Hallam, coupled with the strong straight-line winds noted around Princeton — to the NE of where the N edge of the 2-mi.-wide damage path would have been — suggests to me that the 2-mi.-wide tornado dissipated just NE of Hallam, and a downburst bridged the gap between it and the next tornado spawned by the storm; the downburst was then only apparent outside of the tornado track to the NE. Mainly the way the path swings to the right looks very suspicious, as (going by several Fujita diagrams in Significant Tornadoes) that’s how a tornado family would look if it were plotted inaccurately as a single path — and of course the new tornado/wall cloud would be to the SE of the old wall cloud (the one that spawned the Hallam tornado).

Conversely, it could have been the downburst that caused the Hallam tornado to dissipate by abruptly cutting it off. If the downburst was to be recognized where it is on the map, and to cover the end of the Hallam tonado and the start of the next one, it would have had to cut in front of the Hallam tornado, which would have blocked much of its inflow off.