Sunday, June 2, 2019

Radar data and the Silver Lining Tours incident 5/28/19 south of Lawrence, Kansas

Roger Hill and Silver Lining Tours (SLT) have been getting a bunch of heat on social and other media for two of their tour vans getting rolled during last Tuesday's tornadic storm south of Lawrence (see my post about the weather setting here).

I'm certainly no radar expert, but based on radar data I went through carefully on Saturday, I do think everyone needs to chill a bit before passing judgement about Roger and the tour group being "too close".
A discussion on Storm Track forum has been looking at the early stage of the Lawrence tornado's track via Topeka (TWX) radar, and there was definitely some complex evolution going on with the storm.   This data does suggest that the main tornado was developing a couple miles to the north of SLT's position around the time they were struck by strong winds or some sort of 2nd rain-wrapped circulation coming up from the southwest in an unusual location, which matches statements by Roger.

I also looked at radar data saved from the Kansas City radar (EAX, a little farther away), and can make out two separate circulations at 6:00 pm CDT in the storm-relative velocity field:

This was just before the large tornado developed at 6:05 pm CDT, with the 2nd smaller circulation visible closer to Highway 56.  This 2nd circulation was located about 2 miles (check the scale on the graphic) to the south or south-southeast of the developing large tornado.

Base reflectivity at the same time (below) showed the large developing tornado circulation to be within some rain, with the 2nd circulation located southward within the wet rear flank downdraft (RFD) that was beginning to surge east with this large HP supercell:

Discussion on Storm Track has highlighted this additional circulation to the south of the axis along which the large tornado formed, based on radar images and other information.  Here are radial velocity images from TWX (courtesy of Jeff Snyder on Storm Track) at 5:56 pm, 6:00 pm, and 6:04 pm CDT.  I've marked the locations and tracks of the two circulations.  Notice that it appears the southern circulation moved right over the location where the SLT incident occurred, which lends credence to Roger's description of the incident (click on the image to view it larger):

Dan Robinson on Storm Track put together a graphic suggesting the evolution of the two circulations discussed above.  Here it is, a rather complex evolution prior to the start of the large tornado, with a red "X" marking SLT's location:

Quincy Vagell was shooting video at about 6:00 pm CDT from near the location of the SLT incident,
looking toward the north-northwest:

Notice the lowering visible to the northwest (in spite of rain), which is probably the developing circulation and feature that spawned the large tornado at 6:05 pm, matching what Roger and SLT say they were watching from the southeast.

Quincy describes on Storm Track a "bluish" rain curtain that was moving up from the southwest behind him and to his left.  This was probably the wet RFD containing the small embedded circulation closer to Highway 56 that was not visible, and may have been what hit SLT.

To give some scale and context, I'll mention that my wife Shawna and I watched last year's Tescott, Kansas EF3 tornado on May 1, 2018 (a "classic" non-HP supercell) develop from a distance of about 2 miles to our northwest and north:

This was a similar distance and position to what Roger and SLT had on 5/28 relative to the lowering that they could see to their northwest, which appeared to spawn the large Lawrence tornado a few minutes later.  But, with the wet RFD curtain coming up from the southwest, there was no way to see the 2nd circulation coming with it (from an unusual location within the storm) as they drove back south toward Highway 56 in order to head east and follow the storm from what they thought was a safe distance.

As I mentioned in my prior post, my wife Shawna and I got caught in a somewhat similar surprise situation (strong surging wet RFD winds from the southwest, south of a large tornado) with the El Reno storm in 2013, even though I have years of experience chasing storms as a meteorologist. Luckily, we managed to drive out of the RFD winds without incident.

I think what has sparked accusations of being "too close" in this situation is the characterization of the 2nd / southern circulation shown in the radar images above as a "satellite" tornado, something that implies being really close to a larger tornado.  In fact, this 2nd circulation was separated from the developing main tornadic circulation by at least 2 miles or more, until it moved toward the developing large tornado after striking SLT.  As such, it seems part of a complex evolution that gave birth to the tornado, and not a true "satellite" tornado.

I talked to Roger briefly on Saturday, and know that he is very shaken and more than a little confused by the evolution of what happened last Tuesday.  I think we should all give him the benefit of the doubt on this event.

He and I also talked about swearing off HP storms in the future.... they often surprise and do the dangerously unexpected.

Looking at the bigger picture, maybe spotter and chaser training should start focusing more on large HP storms as a special case with elevated dangers, emphasizing the possibility of wet RFD surges and dangerous winds as an additional hazard south and some distance away from a rain-wrapped tornado.  And, maybe training should teach and emphasize, for safety's sake, that spotters and chasers give large HP storms a much wider berth than what would seem necessary with storms that are more "classic" in nature.  Large tornadic HP supercells are complex and visually challenging, even for experienced spotters and chasers.

Shawna and I are incredibly glad this did not turn out to be another deadly situation, and that everyone with SLT survived.  That’s what's most important.  Just my two cents worth…

- Jon Davies  6/2/19


Rick Schmidt said...

Great analysis, Jon! Almost too complex for me, but I will try to pinpoint our location.(I was following Doug).We were in the vicinity. Awesome explanation!

Lanny said...

Wonderful write up as usual, Jon. Thanks so much for your input!

Unknown said...

This incident should have never happened but yet every seasoned chaser knew it would. Tour companies loading truly unsuspecting passengers into a van and taking them even remotely close to any supercell is a disaster waiting to happen. Whats even worse in my opinion is the fact that everyone is somehow saying this was ok because they were not aware. If you want to know just how "minor" this incident was, ask the local communities which were impacted by a tour company creating a mass casualty incident in their area during a natural disaster. Their opinions should be at the forefront of any excuse being provided by tour operator/owners. 23 of their first responders were tied up transporting or attending to 12 patients while their own community needed them badley. SLT should be billed for the response and backfill this "minor" mass casualty caused. 

The real disaster here is that this will be excused so it will happen again.

Tour companies should be highly regulated and taxed for the potential mass casualties they bring with them. 

I am hoping the NTSB gets involved in this incident to bring needed change to these unregulated interstate tour businesses. Simular to what we did for the Balloon crash that caused 16 hirrific deaths in central Texas. Ill bet the next tour bus accident will be much worse. And, again, we all know its coming.

Jon Davies said...

Thanks everyone for your comments!

The 'Unknown' commenter above is Randy Denzer, and I'd just say in response that the only way to keep situations like this from happening in the future is to outlaw tour groups entirely. Being practical, I don't think that's going to happen any time soon. I also question whether Randy read and absorbed the article in its entirety, including the suggestion of giving HP storms a wide berth, even for experienced chasers. Had I been chasing the Lawrence storm (I wasn't), I might have been near the same location as SLT (2 miles SSE of the visual mesocyclone), following protocol to stay SE of the meso as most chasers/spotters are taught to do. So that gives me pause. But to accomplish what Randy seems to be suggesting, maybe storm chasing should be outlawed altogether :-) :-(. That seems a little drastic.

Unknown said...

It's really easy for people from an armchair to tell people that they messed up. I've been chasing for 25 years I have been close and I have been far. Rodger Hill is one of them better Chaser out there is not the best and to judge him is only for him to do and the people in his care. He has been doing this for years and kept people safe for years. If people think he's unsafe they'll quit doing this his tour. Like I said I've been out there for 25 years and decisions have to be made in a Split Second so everybody can get off their high horse and let the people involved judge for themselves

Unknown said...

I didn't mean to post is unknown my name is James Seitz

Unknown said...

Excellent write-up! I absolutely appreciate the pioneers of our professions and look forward to m,any more adventures in the future. My only extraordinary thought though is similar to within your 2nd to last paragraph. I basically thought that concept was a given already and regularly performed, at all expenses, given the profound element of "multiple lives" at stake for the "unknown". Many of us have seen these southern flanks do crazy things with HP developments and sequences. Even recent events have proven that the "unknown" is somewhat common......and has been documented. Therefore we need not breach that threshold. Did we not learn from them? Personally I believe that one individual's actions, "dangerous" or not, is one thing....especially if they don't include endangering others at the time.... but vans full of people, at the hands of someone else, is completely another domain of sacrifice; and the word "sacrifice" should be a more common approach....Tomorrow is another day, versus endangering for the Now. I've seen touring customers (many even from other countries) that are completely ecstatic about even basic shelf cloud sequences, and sunset structures, and will gladly return for more. I don't believe that any guest would neither debate nor berate a company's decision to "not get too close" due to the imminent dangers of HP event's lack of viewing. And by "too close" I mean completely out of the rain veil and in enough open area to be able to see any new developments....even if it means completely clear of the track, for miles, it is what it is.... There's always another storm cell to view, or day to pursue them....Stay safe out there everybody and I look forward to seeing y'all on the Plains! #SacrificeForLife

Unknown said...

Not sure why it is Unknow... I am Jesse Post

Jon Davies said...

Sorry that some additional commenters are showing up as 'Unknown', not sure what the problem is. I'll have to check that.

Thanks James and Jesse for your comments, and everyone else... I appreciate the discussion!

Unknown said...

Oh don't be so wet! God, from the people who built America and explored the frontier, to people like you. Grow a pair and get some guts. I've been on a storm chasing tour and I was fully aware that something like this could happen. I wanted to get close to tornadoes, that's why I went on the tour.

The very last thing America needs is more government regulation and tax of anything. There is more than enough already.

"Creating a mass casualty incident" - oh please!

Unknown said...

Get him! Some folks don't even want to walk outside due to harmful sun rays, or the threat of a bee sting or who knows what. These tours involve a certain risk/reward. If you don't like it, stay home. This was an isolated incident. I know there are those who "get too close" but natural selection will take care of those who aren't careful. These chasers also help people who live where the storms hit, when possible.

Kathy said...

As a guest of storm chasing tours I am sick to death of reading that I am a naive exploited victim of greedy tour companies. We sign massive waivers, we know the potential danger. The reason we chase with professiinals like Silver Linings is because it is far safer than jumping into a car and trying to do it ourselves as a novice.