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  • Writer's pictureMichael Thornton

Tornadoes, road closures, and flash flooding - April 27th, 2024 Weather Operations

On April 27th, 2024, the Storm Prediction Center issued a Moderate Risk for Tillman County, Oklahoma, with the primary risks being hail up to the size of baseballs, 60 to 80 mph wind gusts, and a 15% significant tornado risk. Weather models agreed that storms were likely to impact Tillman County after 2 PM. I activated our storm spotters at 9 AM with this information and reviewed the newest mesoanalysis and model data. At 10:45 AM, I sent our storm spotters and stakeholders a mesoscale analysis for Tillman County. In this analysis, I wrote the following "Temperatures range from 77 to 78° across the county with dew points between 68 to 69°. Winds are viewing out of the southeast, gusting between 26 to 29 mph. A moderate risk is over Tillman County for the threat of very large hail, wind gusts between 60 to 80 mph, and the threat of tornadoes. SPC mesoscale analysis shows an impressive 4,000 j/kg in SW OK over Jackson/Greer/Harmon counties. For Tillman, We are sitting at 3,500 j/kg. There is a lot of instability in our atmosphere this early in the day. As for bulk shear, there are 50 knots over Tillman County. This is more than enough for storms to grow and maintain themselves and potentially rotate this afternoon. The SPC HREF model is very consistent with the idea that our county could see severe weather after 2 PM. Additionally, CAM models are also supporting this theory."

Around 12:50 PM, the Storm Prediction Center, after coordinating with the National Weather Service in Norman, issued a Particularly Dangerous Situation Tornado Watch for Tillman County. They mentioned that several strong tornadoes were likely. Additionally, very large hail and wind gusts up to 75 mph were possible. By this time, storms were already forming back to the west and southwest of Tillman County, however,

none of these storms were severe. Around 2:30 PM, the National Weather Service informed our agency that the tornado threat for Tillman County was increasing so I posted the following on our social media page "There is currently a Tornado Warning to our Southwest between Crowell and Benjamin, Texas. The National Weather Service has identified that this storm is entering a more favorable environment for tornadoes and as a result, Tillman County could see an increase in

tornado threats through 4:30 PM." It was around this same time that I activated our mobile Emergency Operations Center for storm-spotting activities in the eastern half of Tillman County. At 3:55 PM I wrote another post on our Emergency Management page as the result of a tornado forming to our Southwest near Electra, TX. I informed the residents of Tillman County that while our county was not in a Tornado Warning, a tornado had been identified near the border of our county and to pay close attention. At

Looking SW from NS232 and US-70 at a disorganized funnel cloud. Photo by my girlfriend.

4:20 PM, a Tornado Warning was issued for Tillman County. From that point on, I delegated social media posting and submission of storm spotter reports to the National Weather Service to my girlfriend so that I could focus on communicating with my storm spotters and local officials in the towns impacted. Around this same time, I also activated the Sheriff's Office for storm-spotting duties. As my girlfriend and I sat at NS 232 and US-70, the once hazy storm started to become clear and I noticed a lowering in the storm, but nothing too concerning. At 4:23 PM, a TCEMA Storm Spotter near Hollister called me and we discussed an area of low-level rotation on the Northern side of the storm. This area of rotation produced a very brief funnel cloud before becoming disorganized. The Storm Spotter called me again at 4:37 PM and we discussed a wall

Looking northwest at the wall cloud from NS 232 and US-70.

cloud that was forming to my northwest near Hollister. As the storm continued pushing Northeast through the county, the wall cloud became disorganized and the storm as a whole became less of a tornadic threat and more of a straight-line wind/hail threat as noted by its structure and radar data. The next threat came at 5:35 PM, when a Tornado Warning was issued for the City of Grandfield for a line of storms that were pushing into Tillman County from

The HP Supercell as it moved into Grandfield.
Picture courtesy of the Grandfield City Manager.

Northwestern Texas. The Fire Chief for Grandfield pulled up next to me not long after the Warning had been issued and I informed him to sound the sirens in the City. My girlfriend posted the information to our Facebook page and then alerted the National Weather Service that sirens were being sounded in the City of Grandfield. This, of course, was a radar-indicated warning because the storm was High-Precipitation. This meant that radar data was supportive of a tornado, however, because there was so much precipitation, we could not confirm it. Even when the storm came within 8 miles of my location, I could not identify any features. As a result, I chose to drive back into Grandfield from US-70 and then go a mile north on US-36 where I had a better and more safe view of the storm. At 6:05 PM, I received a report of one-inch hail southwest of Grandfield. Eighteen minutes later, the National Weather Service informed us on Slack that a storm in North-central Wichita

Reflectivity and Velocity data at 6:54 PM.

County showed signs of rotation 7 to 9 miles southwest of Burkburnett, Texas. This is important to note, because Burkburnett is southeast of Grandfield by 12 miles, meaning that the rotation could have pushed into rural parts of southeastern Tillman County downstream. At 6:31 PM, a TCEMA Storm Spotter reported dime-sized hail in Grandfield. My girlfriend was quick on the draw and immediately informed the National Weather Service of this information in NWSChat. Nearly ten minutes later I recorded 60 mph wind gusts at the intersection of US-70 and NS239, a mile west of Grandfield. When the clock struck 6:44 PM, the National Weather Service issued a new Tornado Warning for Grandfield and southeastern parts of Tillman County for the rotation that had been mentioned earlier near Burkburnett. The velocity couplet was quite intense and I informed the sheriff of my interest in shutting down US-70 east of Grandfield as I anticipated the rotation to go

over US-70 near Devol in Cotton County. Without hesitation, the Sheriff said, "Let's go!" As we drove into town, the wind and rain increased. In addition to radar being supportive of a tornado, the storm was entirely wrapped in rain, so anyone driving toward Devol wouldn't be able to see a tornado. The sheriff and I set up just east of the US-36 and

Flash flood waters receding from the highway.

US-70 intersection and shut down US-70 going towards Devol from Grandfield. We kept US-70 closed for ten minutes as rotation passed over US-70 and into Devol. The Sheriff performed a brief rapid damage assessment and found no damage, however, reported 50 mph wind gusts and informed me that grass near the rotation was lying flat on the ground. Shortly after, my girlfriend and I learned that the tornado had uprooted trees along US-70 and damaged homes in Devol. The right call was made that day to shut down US-70 from Grandfield to prevent people from driving into the storm. After I opened US-70, I was informed of ongoing flash flooding a few miles north of Grandfield on US-36. In between EW190 and EW191, the Grandfield Fire Chief, my girlfriend, and I came upon flash flooding occurring in a ditch. Dirt was scattered all over US-36

which indicated that the water had come over the road at one point. My girlfriend and I drove another mile north and found additional flash flooding on the opposite side of the road. Water from the east side of the road was pushing down into a culvert and flowing to the west side of the road into a farmer's field. This kept the water from overflowing onto the road.

A double rainbow over Grandfield. Photo taken by my girlfriend.

A short time later we ended our mobile operations. Over the next few hours, 21 tornadoes occurred in the State of Oklahoma, causing Governor Stitt to sign a State of Emergency for 12 counties. Multiple communities were significantly impacted and unfortunately, at the time of writing this four people lost their lives on April 27th from severe weather. In closing, I'd like to send my thoughts to those who were affected by these storms.

About the writer: Michael Thornton graduated from Rose State College majoring in Emergency Management. Currently, he is the Director of Tillman County Emergency Management, an Oklahoma Certified Emergency Manager, and the SW Oklahoma Emergency Management Association VP Alternate. In 2024, he was awarded the OEMA Innovator Award for his severe weather operations in Tillman County.



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