2020/05/08

Inspection of Tornado Damage using Satellite Imagery

March 3rd, 2020 a deadly tornado touched down in Putnam County, Tennessee. It's 8.2 mile path destroyed more than 100 homes and left a normally happy community heartbroken and distraught. A week on, this is an analysis of what happened using GIS data and aerial imagery.

Inspection of Tornado Damage through Satellite Imagery

How do we get to the above map? The track was provided by National Weather Service (NWS). The track buffer was made using attribute data provided by NWS.

NWS update for Putnam County Tornado
Regions affected: Putnam County, City of Baxter, City of Cookeville
Max Rating: EF-4
Max Winds: 175 mph
Path Length: 8.2 miles
Path Width: 500 yards
Time on the ground: 8 min
Forward speed: 65 mph
Buildings destroyed: 100
Road Crossings: 35


Affected Area (500 yard buffer of tornado path)
Buildings within affected area: 1,812
Landuse:
Land use / Land cover Acres Percent
Agriculture 1,220.34 38.78%
Commercial 194.65 6.18%
Industrial 56.76 1.80%
Public/Semi-Public Uses 113.28 3.60%
Residential 1,052.35 33.44%
Transportation 226.80 7.21%
Vacant 283.03 8.99%

Survey summary:
A violent tornado tracked across western and central Putnam County, resulting in numerous destroyed homes, 30-35 of which were destroyed completely, and caused 88 injuries and 18 fatalities. The tornado began 2.5 miles northwest of Baxter where it produced EF-0 damage for 2.7 miles as it crossed Gainesboro Highway. The tornado intensified to EF-1 and EF-2 intensity in the Prosperity Pointe subdivision just north of us 70N/Nashville Highway and further intensified to EF-3 as it crossed Bloomington Road and Clemmons Road, severely damaging several homes. The tornado then became violent for 0.8 miles as it entered the area around McBroom Chapel Road, where it reached EF-4 intensity, completely destroyed over a dozen homes, and caused numerous fatalities with the heaviest damage concentrated on Hensley Drive. EF-4 damage continued eastward to Echo Valley Drive, where an apartment complex was completely destroyed. EF-2 and EF-3 damage continued eastward for 2.0 miles, affecting homes along us 70N/W Broad Street, before rapidly coming to an end near n Franklin Avenue just west of Cookeville Regional Medical Center.

2020/05/07

Mean Elevations and Slopes of Tennessee Counties



Elevation units are feet, and slope units are degrees. Based on analysis using 10 meter DEMs.

Top Five Mean Elevation Counties: Johnson (2904.53'), Unicoi (2754.86'), Carter (2654.64'), Sevier (1970.47'), Cumberland (1793.50')
Top Five Mean Slope Counties: Unicoi (20.10°), Sevier (17.24°), Johnson (16.73°), Carter (16.38°), Hancock (16.01°), Cocke (15.26°)


County Slope_Mean Slope_STD Elev_Mean Elev_STD
Anderson 12.68 8.80 1292.74 563.60
Bedford 4.13 4.60 840.61 114.80
Benton 5.31 5.02 468.24 72.67
Bledsoe 7.52 6.71 1601.02 429.28
Blount 12.88 10.54 1411.09 718.40
Bradley 5.31 4.93 853.80 93.81
Campbell 14.96 8.69 1583.08 454.08
Cannon 9.83 8.54 1001.09 182.71
Carroll 3.52 3.06 462.33 58.26
Carter 16.38 9.81 2654.64 787.57
Cheatham 9.19 7.39 594.66 103.34
Chester 3.85 3.38 480.23 53.59
Claiborne 13.99 8.30 1482.68 309.92
Clay 12.43 9.99 803.74 137.30
Cocke 15.26 10.13 1738.72 745.83
Coffee 3.90 5.81 1088.69 119.77
Crockett 1.77 1.63 339.62 36.62
Cumberland 6.79 5.81 1793.50 205.51
Davidson 6.93 7.06 586.80 121.13
Decatur 5.40 4.73 142.72 20.44
DeKalb 10.51 9.46 870.45 162.40
Dickson 7.01 5.12 705.97 103.97
Dyer 1.43 2.46 292.36 43.73
Fayette 2.52 2.46 392.83 63.14
Fentress 9.16 7.81 1492.17 255.99
Franklin 6.43 6.89 1168.15 323.39
Gibson 2.13 2.06 366.59 51.53
Giles 7.67 5.98 822.75 122.02
Grainger 10.81 8.20 1282.26 250.31
Greene 9.83 8.69 1534.04 512.59
Grundy 6.91 6.96 1729.67 320.27
Hamblen 6.68 5.88 1246.31 132.15
Hamilton 6.91 6.84 964.84 371.16
Hancock 16.01 8.74 1538.72 261.40
Hardeman 3.76 3.70 457.72 73.56
Hardin 5.07 5.18 508.68 118.10
Hawkins 12.60 9.34 1414.97 253.99
Haywood 1.51 1.67 331.73 39.55
Henderson 4.06 3.39 490.68 55.08
Henry 3.55 3.30 467.27 66.87
Hickman 9.81 6.97 685.17 114.21
Houston 8.43 5.48 576.85 104.52
Humphreys 7.78 6.25 564.28 127.14
Jackson 14.50 9.62 780.70 156.60
Jefferson 6.58 6.31 1146.02 169.32
Johnson 16.73 9.31 2904.53 514.64
Knox 6.85 5.94 1004.30 121.93
Lake 0.49 1.20 279.92 12.74
Lauderdale 2.38 3.65 301.44 68.54
Lawrence 5.58 5.28 876.66 98.05
Lewis 9.04 6.41 848.03 90.27
Lincoln 6.06 5.66 841.89 111.79
Loudon 6.37 4.98 915.74 90.13
Macon 9.59 7.84 862.89 104.61
Madison 3.03 3.16 435.52 62.40
Marion 9.77 8.42 1307.63 489.69
Marshall 4.89 5.31 816.58 133.78
Maury 6.25 5.52 737.37 108.14
McMinn 6.59 5.83 912.80 148.42
McNairy 4.00 3.43 482.03 51.84
Meigs 5.85 5.59 807.15 93.24
Monroe 12.60 9.82 1438.11 734.46
Montgomery 4.93 4.42 534.74 80.46
Moore 8.54 6.25 974.91 113.31
Morgan 10.97 8.10 1492.93 342.80
Obion 3.04 4.25 349.25 54.10
Overton 9.45 7.40 1206.61 307.17
Perry 10.92 7.18 602.85 129.32
Pickett 11.09 8.52 1054.35 295.84
Polk 13.99 10.12 1372.48 507.54
Putnam 9.10 8.23 1189.20 351.15
Rhea 7.02 7.05 1149.67 447.65
Roane 8.61 7.13 910.28 161.04
Robertson 3.75 3.90 671.02 88.38
Rutherford 2.72 3.54 683.15 126.36
Scott 13.84 8.60 1536.96 314.72
Sequatchie 8.39 7.18 1654.80 477.38
Sevier 17.24 10.78 1970.47 1226.77
Shelby 2.23 2.74 287.00 50.06
Smith 9.97 7.36 677.02 144.73
Stewart 7.11 5.50 508.11 94.17
Sullivan 11.27 9.01 1700.57 426.13
Sumner 5.55 5.67 695.15 144.09
Tipton 2.44 3.11 311.85 58.80
Trousdale 6.86 5.96 616.25 125.99
Unicoi 20.10 9.86 2754.86 680.49
Union 11.15 7.99 1231.62 164.21
Van Buren 7.29 6.55 1578.60 333.18
Warren 5.08 5.50 1109.30 246.73
Washington 8.88 8.09 1714.72 276.72
Wayne 9.06 6.58 787.47 142.44
Weakley 2.52 2.50 394.16 47.82
White 7.05 6.59 1192.64 333.47
Williamson 6.65 5.74 782.71 99.28
Wilson 4.31 4.05 653.76 135.52

2020/04/29

United States of Disasters

United States of Disasters

One month ago my house was partially destroyed by a wind storm. Or perhaps it was a tornado. I've been displaced and living with my brother since. I've not been able to see my girlfriend due to the COVID-19 epidemic. It sure feels like the end of the world. So I decided to test my suspicions that disasters seem to be happening more frequently of late.

Using Federal Emergency Management Agency (FEMA) data regarding Disaster Declarations for States and Counties I started looking at the Upper Cumberland Region as a way to focus my analysis. The Upper Cumberland's worst years previously for disasters were 2003 and 2005 where there were a total of 17 declared disasters in the region. At the time I calculated it, we were exactly 114 days into 2020 and we had already declared 32 disasters. In less than a third of the time, we had declared nearly double the disasters. So I calculated the frequency to determine that we were in fact experiencing disasters at a rate 5.6 times our worst year ever.

The Upper Cumberland is comprised of 14 counties. We're a subsection of Tennessee, primarily located in the middle region with one county in the east. Is what's happening here happening elsewhere in the United States?

I decided to look into disasters in a more broad way and created the above map which represents modal disasters. That is to say, what disaster occurs in that county the most. Despite what legions of people on Reddit told me they felt it should look like, the data actually bears this out. Those are the modal disasters of the contiguous United States. You don't have to like it, but you do have to accept it.

The good news is that you're not insane, this year is truly terrible since so far we've accumulated exactly 7395 disaster declarations (really two [1, 2] nationwide declarations regarding COVID-19) in 114 days. Compare that to the previous year where the entire of 2005 the USA had 4636 declared disasters (mostly hurricanes). If you're interested in the frequency, that works out to around 5.1 times the frequency of disaster declarations of the worst year on record since we've been keeping track in 1959.

Is this really fair given that we are living through an unprecedented event for the modern era? No not really. But numbers are numbers and I've been bored. so without further adeau I present the full series of the United States of Disasters.

Declared Disasters - Chemical Declared Disasters - Coastal Storms

Declared Disasters - Dam and Levee Declared Disasters - Drought

Declared Disasters - Earthquake Declared Disasters - Fires

Declared Disasters - Fishing Loss Declared Disasters - Floods

Declared Disasters - Freeze Declared Disasters - Human Caused

Declared Disasters - Hurricane Declared Disasters - Mud or Landslide

Declared Disasters - Other Declared Disasters - Severe Ice Storms

Declared Disasters - Severe Storms Declared Disasters - Snow

Declared Disasters - Terrorist Declared Disasters - Tornados

Declared Disasters - Toxic Substance Declared Disasters - Tsunami

2020/03/21

Tennessee COVID-19 Data

I am maintaining this spatial temporal dataset regarding the unfolding COVID-19 epidemic in Tennessee.

I'll be updating this dataset after 2pm daily when the state provides the numbers for each county. This is not a "live" dataset. I have to key each number manually, and I have to validate every number that isn't from my official source.

This is open data that I am sharing. Please let me know if you end up using this it for something. As always, feel free to share.



For use, please cite as follows:
Sutherland, Charles J. (2020) Tennessee COVID-19 Data. Google Sheet. Retrieved from https://docs.google.com/spreadsheets/d/1wcNiiWWYOFbk4m2hb92A2kgVoJ2b0E77jcdxGsns1Kw


2020/03/17

The Geology of the Twin Arches in the Big South Fork

The Twin Arches are a large pair of arches formed along a ridge just inside Scott County, Tennessee. They are topped by an erosion resistant rock now being called the Rockcastle Sandstone. Below that is the Fentress Formation, which tends to weather more rapidly. These arches both formed by a process of excavation where the cliff lines are receding on either side of a ridge towards one another. The base of the cliff weathers more rapidly than the top, creating large rock shelters. Eventually the rock shelters on either side of the ridge intersected one another creating an arch. The arch continues to grow and one day, sometime long from now, it will fail.

North Twin Arch, Big South Fork NRRA, Scott County, Tennessee South Twin Arch, Big South Fork NRRA, Scott Co, TN


2020/03/03

March 3rd 2020 Tornado, Cookeville and Putnam County, Tennessee

Some photos from around Putnam County this morning. It's a bad situation for lots of people. Homes and lives have been lost. I feel nothing but sorrow today. These were the most painful photos I've ever taken.

If you feel moved to provide assistance, donations, or anything at all, please email helpnow@putnamcountytn.gov. They will coordinate with you. While Governor Lee's declaration of a state of emergency will help allocate funds to help those in need, it won't be a quick process. We need good neighbors to help.

Stay safe y'all.

March 3rd, 2020 tornado damage, Putnam County, Tennessee 7 March 3rd, 2020 tornado damage, Putnam County, Tennessee 27 March 3rd, 2020 tornado damage, Putnam County, Tennessee 20 March 3rd, 2020 tornado damage, Putnam County, Tennessee 18 March 3rd, 2020 tornado damage, Putnam County, Tennessee 10 March 3rd, 2020 tornado damage, Putnam County, Tennessee 24 March 3rd, 2020 tornado damage, Putnam County, Tennessee 29

2020/02/28

How to do a Cleanup

Illegal dump, The Old Mill Cave Cleanup, White County, Tennessee 1 Stages of a cleanup
  • Identify an illegal dump site or graffiti ridden location
  • Secure landowner permission
  • Build your team
  • Build partnerships
  • Set a date
  • Gather volunteers
  • Resolve legal and logistic issues
  • Contact the media
  • Obtain supplies
  • Execute the cleanup
  • Conduct a post-cleanup analysis

Identify an illegal dump site or graffiti ridden location

It may be that you already know a place that needs to be cleaned. If you don't talk with local officials and folks who spend time outside. Someone can point you to a place in need.

Knowing where to clean is only part of the process though. You need to know whose property you would be working on. If you're in Tennessee, you can use the Tax Assessor webpage to explore who owns what. Alternately your friendly neighborhood GIS professional can help you get at this information.


Secure landowner permission

Bob Keats, Birdsong - Tennessee River Freshwater Pearl Farm, Benton County, Tennessee You'll want to reach out to the landowner early on in planning to make sure they are fine with you proceeding. Keeping the landowner involved at every step is a good idea as well. Many landowners will be out there with you the day of the cleanup. You're doing them a favor. Some landowners may be concerned with liability. Look in the section titled Resolve legal and logistic issues for information on how to deal with this.

Be sure to get their permission in writing. Chances are it isn't necessary, but there seem to be a lot of people out there who flip flop. You want to make sure you're working with a stable predictable partner before proceeding.


Build your team

Ian Smith, Chuck Sutherland, Megan Atkinson, Andrea Kruszka Suggested Cleanup Team
  • Chair
  • Communications
  • Safety
  • Technical

While it doesn't have to fit the above form exactly, each of the appointed committee members play an important role.

The chair serves as an executive who leads meetings, makes duty assignments, and provides energy and motivation. Other team members may hit snags with their jobs, they should communicate issues with the chair and the chair should work to resolve issues quickly.

Communications is the one of the most important committee members. They keep track of meeting minutes, keep people informed of their action items and jobs, and manage contact with any external groups as defined by the team and chair.

Safety's job is to make sure all precautions are met prior to the cleanup. This includes checking people in, making sure liability waivers are signed, observing the cleanup and preventing people from being hurt. This person may have to tell people to stop doing things which are unsafe so choosing someone with a commanding personality is important.

Technical team members are responsible for any rigging, implementation of haul lines, or any other technical engineering that needs to be done to execute the cleanup. Not every cleanup needs technical members.


Build partnerships

Cleanup crew at lunchtime, Copeland Cave Cleanup, Cookeville, TN You can't do a cleanup alone. You'll need a team of people close to you that you trust to get things done quickly and accurately. Ideally these people come from different walks of life and are able to bring the diverse skills necessary to successfully execute a cleanup.

Partnerships may be the organizations your team members belong to, or who they have good working relationships with. Ideally you'll want partnerships in local government at a few levels, state government in conservation organizations, NGOs whose mission overlaps with yours, and other community volunteer organizations that can provide support and manpower.

Organizationally local governments can all be quite different, so there is no catch all for who you need to work with. You'll need to know someone who can help you haul off and dispose of the trash and tires. Some governments have clean commissions, all governments have solid waste departments. Sometimes you'll want to talk to the mayor yourself, other times you'll want to deal with lower ranking officials. Generally when governments learn you're doing a cleanup they'll bend over backwards to assist you. Everyone wants a cleaner more beautiful landscape, especially those seeking re-election.

Every state has a water resources department. In my experience they are always willing to throw their support behind a cleanup since illegal dumps affect water quality. Other state level organizations which may be relevant to at least talk to would be division of natural resources or whatever state fishery and wildlife exists.

NGOs, or non-government organizations, are specialized in their approach, mission, and values. Lots of conservation NGOs love to throw their weight behind a good cleanup. It's likely you can partner with several of these organizations for increased effectiveness. By no means is this a complete list, but I've had good luck working with these organizations in the past:
The Nature Conservancy
The Sierra Club
Boy Scouts of America

Community volunteer organizations worth reaching out to could include student organizations at your local college. They often require a number of volunteer hours yearly in order to maintain their charter. Fraternities, sororities, departmental clubs, and professional organizations are all looking for volunteer opportunities. Local hiking groups, local churches, the Rotary Club, the Chamber of Commerce, and other similar organizations are all worth talking to about partnership opportunities or identifying other partners and volunteers for your cleanup.

As a final note, if one of your organizations has 501(c)3 tax free status, you'll want to take advantage of them purchasing supplies. You'll want to be able to have them take earmarked donations and get them to purchase supplies later.

Set a date

The most intimidating part of the process is setting a date. You may be inclined to overthink this - do not. Here's what you need to consider and here's how you should proceed.

Cleanups are best in cold weather. Late Fall, Winter, early Spring are ideal times since vegetation, snakes, ticks, insects, and poison ivy will be less of a concern. Vegetation is the most notable problem with cleanups since plants will envelope trash making it difficult to impossible to remove, and also hiding it.

You'll want to schedule two dates for a cleanup. A primary date, and a backup. Weather happens and we have no control over it. A backup date gives you some stability towards executing the cleanup in the event of rain, snow, or some other freak weather event.


Gather volunteers

Trog Sink Cleanup, Cookeville, Tennessee 6 Your partners should help you with this process. Ideally they each have their own unique network of volunteers that they can reach out to. Look back at who your partners are and see how they can each best build a pool of reliable volunteers.

Facebook is a good tool for building public awareness and momentum for a cleanup. Create a public event page and invite all your friends who would be interested and would be able to participate. Have your partners do the same.


Resolve legal and logistic issues

Dirt Cave Cleanup, Jackson County, Tennessee Everyone's concerned about liability. Know your state's liability laws. This may mean you consult with a lawyer. If you do, make sure that they know this is for the purpose of making the community a better place and try to save yourself a legal fee.

Your volunteers will need to sign liability waivers, and your landowner will want the best legal protection in place to protect them from litigation should something go awry. To this end, you should think about having a "Safety officer" for the cleanup. Whatever this person says, goes. You'll need to make decisions to mitigate any legal problems up front. For example if children are at a cleanup, do not put them on a steep hill with metal and glass. Kids are good for working the road near the cleanup, unless it's a busy road.

Contact the county roads department early in your planning process and request them to put up signs the before the cleanup encouraging automobile traffic to slow down.

You'll need to plan for a prepare the landscape for your cleanup. If there are steep hills or cliffs then you'll need rope and the people who know how to best use it. If there is lots of vegetation (even dead) then have chainsaws and folks who know how to use it. If there is graffiti, spot clean it in a few places to see what works and what doesn't. Sometimes this step requires some creativity, so this is a good time to bring your team together to creatively solve problems in advance of the cleanup. Try to anticipate problems and address each one individually. Talk through solutions because one person doesn't have all the answers.

Make sure you have solved where the trash is going, who is taking it there, and how they are taking it there. Make sure you know where the tires are going. Often household trash and furniture / construction materials need to be separated. Have plans for this. If you are using earmarked money or working with a grant make sure you've addressed all the needs and concerns of whatever is funding you.


Contact the media

Upper Cumberland Grotto, TTU Cave Cleanup, Putnam County, Tennessee 1 This step may sound self-aggrandizing, but I feel it's one of the most important steps. If we are to make permanent change in the world then we do so by education. Educating people and shifting their values is arguably the most important thing a cleanup does since you're potentially shifting public opinion on matters of conservation. Most people agree that we should keep the land free of trash and graffiti. If they are on the fence and see overwhelming public support for it, they are likely to shift their attitudes

Make sure your local media representatives know the date, time, and location of your cleanup. Have someone appointed to deal with them directly who can eloquently explain the importance of doing cleanups. Provide them with necessary media, like before and after photos, and photos of the cleanup process.


Obtain supplies

Inventory in advance of the cleanup the tools you need and who will be bringing them. If you're a 501(c)3 tax except organization, or you're partners with one, get them to make the purchases.

Every cleanup needs: gardening gloves, leather work gloves, loppers, hand shears, drinking water, and snacks.

At larger cleanups you may want to serve lunch. Maybe you can find a local pizza place that will cut you a deal? Maybe a local restaurant or caterer will want their name on your sponsors? Lunch can usually be worked out if you invest some time looking. Sometimes a partner may already have a plan for this.

Larger cleanups will also require a more complex assortment of tools. Rope, ropework tools, chainsaws, shovels, pickaxes, wenches, and haul systems may be needed. Tables and chairs for eating and planning also may be required.


Execute the cleanup

The day of the cleanup comes. Like anything important, prepare as much as you can in the days before, and arrive there early. Someone's job should be making sure volunteers are signed in and have all their liability forms in place. Someone should address the group and explain what the objective is, introduce the safety officer and explain their position, as well as set times for breaks, lunches, and finishing. They should communicate safety and logistical issues to the group to prepare them for the day's work. The person dealing with the media should be taking photographs. It is a good idea to make this person in charge of communicating with the group because it is likely they will get spread out throughout the course of the cleanup. They should have a backpack with gloves, trash bags, and small tools because people will be needing these throughout the day.

Stage trash alongside roads for quick pickup at the end of the day. Designate a team of people to do a sweep at the end of the cleanup to make sure no one leaves any personal belongings, tools, or trash behind.


Conduct a post-cleanup analysis

As a final step, set a meeting within a few days after you've completed the cleanup that should be attended by your team and maybe a few of the volunteers. You'll want to discuss what worked, what didn't work, and what could be improved. Write it all down and keep that record somewhere. Sometimes the space between cleanups can be a while and it's easy to forget what we've learned along the way.


Last, but certainly not least, Maureen Handler made available some planning spreadsheets used by the SERA Karst Task Force.

2020/02/13

So You're Curious About Caving?

Laurel Abernathy, Kelli Lewis, Blue Spring Cave, White County, Tennessee

You're curious about caving? It's easy to understand why! Maybe you've seen photographs of caves and you're curious to see these places with your own eyes. Maybe you heard about a friend's excellent adventure through a local cave system and how challenging and rewarding it was for them. Maybe you're looking for the next extreme sport to master or maybe you're interested in learning about history, or a science that's practiced in caves. Whatever your reason, there's a great group of folks who are here to help you on the next leg of your adventure.

Ashley Williams, Secret Cave, Putnam County, Tennessee 1 The National Speleological Society (NSS) is the organization I belong to that is about caves and caving. There are local chapters called grottos. I am a member of a few of these across Tennessee, but the first grotto I belonged to, and the one where I focus most of my energy is the Upper Cumberland Grotto. We are based out of Cookeville, Tennessee.

Grottos duties are to intercept would-be cavers and help introduce them to the world of caving. There are different rules for safety and conservation down there, and you're not born knowing them, so we try to handle that education. We develop landowner relations, we do community outreach and education, we do cleanups, we like to eat food and drink beer, but most importantly we go caving.

Depending on where you live you may or may not be nearby to caves or a grotto, which is usually based out of a city. You can check at Caves.org. look for the link that says "find a caving club near you". Or you can look at this handy map I made which shows the nearest grotto to where you live (note that it's not always accurate to say that a grotto is located somewhere).

Regardless of your proximity to my club, let me extend a formal invitation to come join us at an Upper Cumberland Grotto meeting sometime. We alternate meetings between business and socials. At business meetings we have presentations and usually a handful of us go out for beer and food afterwards. We meet at a restaurant, or maybe the bowling alley, and we hang out and have fun. This is where a lot of caving trips get organized. If you have any questions you're welcome to reach out to me, or the grotto officials that you locate through the above links. We always love to hear from new cavers.

The NSS produces brochures which cover information about the caving community, responsible caving, and more. This is a great place to get started learning about caving.
Caves.org/brochure/index.shtml

Below are some selected readings about caving. These are generally written with a novice caver in mind, so don't expect to be overwhelmed.

Dirt Cave Cleanup, Jackson County, Tennessee

Gear for Caving in Tennessee

Why We Don't Share Cave Locations

Vandalism, Dirt Cave, Jackson County, Tennessee 1
Anne Elmore doing a Change-over, Halloween Grotto Party at Jay Green's House, Putnam Co, Cookeville, TN

The Role of Grottos in the Caving Community

The Role of Grottos in the Outside Community

Cleanup, Pilot Knob Cave, Jackson County, Tennessee

2020/02/10

Tornadoes of the Upper Cumberland

Possible tornado, Ken McDonald, Putnam County, Tennessee

With tornadoes touchdowns in my neighborhood this last week, I am reminded of this very nice dataset regarding tornadoes. I thought that a focused regional analysis may be appreciated. Below you can see tracks of tornadoes from 1950 - 2017 that are displayed by EF rank (tornado intensity). The tracks are approximations based on a start and end point, which is why they all appear perfectly strait. Note that the path of most of the points is from south-west to north-east. This follows the prevailing winds of the region.

Tornadoes of the Upper Cumberland: 1950 - 2017

Many of the following charts I show will have some minor errors in them that result from data smoothing. Please take these with a grain of salt. The first three charts show temporal trends in tornado behavior in the UC.

Yearly Tornado Activity


From this chart one can see that there have been more lately, but it is hard to draw long term conclusions from this data. The data tapers towards our current date as a result of the smoothing process. Other considerations towards the apparent rise is recent tornadic activity may be accounted for by sampling bias. Increasing population make the likelihood of observing a tornado, as well as a report being made about a tornado is more likely to be done in a more interconnected communication oriented society.

Daily Tornado Activity Throughout the Year (by Julian day)


The most distinct peak occurs around Julian day 90, which approximately is the end of March and beginning of April.

Hourly Tornado Activity


Peak tornado hour is shown to be 4pm by this data.

Length of Tornado Tracks in Miles


Width of Tornado Swath in Yards


Histogram of EF Scales


Software: ArcMap 10.7, Excel, Orange