Questions About the May 28 Storm

On Sunday, May 28, 2017, severe weather impacted the Longview Texas area with heavy rain, winds, and an estimated EF-1 Tornado. Below is some information regarding the most frequently asked questions from the severe weather notification process during that storm event.

Q. Why was a siren test conducted on May 31, June 7, and June 14? What were the results of these siren tests?
A. Some residents have indicated that they did not hear the sirens on May 28 during the storm activity. The test was conducted because safety is our number one priority and we want to make sure the sirens are working properly.

May 31, 2017 Test: 
During the May 31 test, all twenty of the city’s strategically located sirens sounded as they are designed to do.Additionally, the testing revealed that three of the sirens did not rotate fully. The most recent testing of the sirens conducted on March 1 showed there were no malfunctions. It is possible these three sirens were damaged in the storm. These sirens were scheduled for maintenance as soon as possible, and the technicians repaired the non-rotating sirens on Friday, June 9. The three sirens that did not properly rotate and were subsequently were located at 1600 Blueridge Parkway, 610 E. Loop 281, and 1602 W. Cotton St.  

June 7, 2017 Test: 
During the regularly monthly siren test on Wednesday, June 7, only eight of the twenty sirens were confirmed to work properly. The electronic equipment that relays the signal to the sirens was initially damaged during the storm on Sunday, May 28. While the electronic equipment continued to work during last week’s test and all sirens sounded on May 31, the damaged electronic equipment did not properly work today. The affected electronic equipment was ordered and repaired as quickly as possible. On Friday, June 9, technicians worked to make repairs to issues associated with the electronic equipment as well as the siren rotation. 

June 14, 2017 Test: 
All 20 of the City of Longview’s emergency warning sirens sounded and rotated during the June 14 test of the system. However, a timing issue was identified which will be addressed as soon as possible. During the test, the sirens sounded for five minutes as scheduled, but only rotated for three minutes. It is believed that this was due to a setting within the electronic equipment. These settings will be examined and adjustments will be made as soon as possible. 

June 21, 2017 Test:
The emergency warning siren system operated correctly with 19 of the 20 sirens sounding and rotating properly. Siren 16 located near the Spring Hill water tower did not sound or rotate due to a signal communication issue. Maintenance will be conducted to address the issue with that siren. Following repairs, an individual test of that siren may occur. The next system-wide test will occur on the regularly scheduled test on Wednesday, July 5. 

Read the news release about the siren test results

Q. What were the results of the previous siren test on Wednesday, March 1?
All sirens were tested as working properly. Note: the monthly siren tests in April and May were cancelled due to weather conditions on those scheduled days. However, the sirens were successfully activated on April 10 and May 11 for weather warnings.  

Q. How often are the sirens tested? 
Sirens are tested on the first Wednesday of the month at noon unless there is a threat of severe weather on that day. Monthly tests are a common practice among communities with sirens.

Q. Do the sirens work if the power goes out? Did electrical issues from the storm impact the sirens going off on May 28?
All sirens are equipped with a battery back-up at each location, which are designed to provide power for the siren to continue running for approximately 15 minutes.

During the siren activation in the May 28 storm, the City’s Emergency Communication Center was hit by a series of large electrical surges that caused damage to the network computer, lights, auxiliary computer, and radio associated with the siren system. Staff were able to audibly verify that the siren nearest the communication center was activated. We cannot conclusively determine whether the power surge did or did not disrupt the siren activation, but we are taking steps to mitigate the threat of power surges in the future.

Specifically, around 5:15 PM, the Communications Center experienced three very strong power surges.  The Center lost its lights, all of the auxiliary computers shut down, the emergency generator went into an “auxiliary alarm” status, and two important pieces of equipment were destroyed.  One was a Motorola mobile radio attached to the PSC digital recording system.  Estimated value of replacement on that unit is approximately $5,000.  The second piece of equipment was a network switch attached to the Early Warning Siren (EWS) Activation Computer.  This device allows dispatch staff to pull reports off of the computer and share them via email.  That device is available off the shelf for around $40-$50.

Q. Why wasn’t a tornado warning issued for Longview? Has anyone spoken with National Weather Service?
Tornado warnings are issued by the National Weather Service. The protocol in Longview is to activate the sirens when Gregg County has been placed in a tornado warning by NWS. In the case of May 28, the southeastern portion of Gregg County was placed in a tornado warning at 5:11 p.m., but that warning didn’t specifically include Longview. The sirens were activated for approximately twelve minutes from 5:15 – 5:27 p.m. based on the warning for Gregg County. The sirens were deactivated at 5:27 p.m. when the City of Longview Public Safety Communications staff were informed by our local SkyWarn representative monitoring the conditions that the storm and related warning did not appear to be a threat to Longview.

Prior to the tornado warning, the National Weather Service issued a severe thunderstorm warning at 4:50 p.m. It is not the City of Longview’s standard protocol to activate the sirens during a severe thunderstorm warning.

It is important to note that the day after the storm, the National Weather Service estimated that a EF-1 tornado started at 4:53 p.m. 6 miles northwest of Longview, concluding at 5:03 p.m. 4 miles south-southeast of Longview. By the time the Gregg County tornado warning had been issued by the National Weather Service, the tornado had already passed through Longview.

City staff spoke with the National Weather Service to discuss why a tornado warning wasn’t issued for the Longview area in this case. Representatives with the NWS stated that no tight circulation was noted and no reports of funnel clouds were received from storm spotters, law enforcement, or the public, accordingly no warning was issued. Radar operators with NWS did not see sufficient data to support issuing a tornado warning for Longview.

Q. When was the last time the system was evaluated for siren coverage and possible need for more sirens? 
The upgrade of the siren system was completed in 2011 – 2012, which included replacement of the siren heads and relocation of some of the sirens.  At that time, the current system of 20 strategically located sirens was evaluated as adequate for audible outdoor overlapping coverage of the majority of the community.  The sirens are designed to be heard outside and may not necessarily be heard when inside a structure. See Coverage Map

Q. Can the sirens be turned up / made louder?
The siren volume is set to the maximum level available, which is 130 decibel output at 100 feet. The effective range is 70 decibel at 6200 feet.

Q. Has tree growth decreased the impact of sirens?
We do not believe that tree growth has had any significant impact on siren effectiveness.