Officials in Hannibal are still trying to determine why the city's outdoor warning system didn't fully operate Sunday afternoon when a tornado-warned thunderstorm was bearing down on America's Hometown.

Officials in Hannibal are still trying to determine why the city’s outdoor warning system didn’t fully operate Sunday afternoon when a tornado-warned thunderstorm was bearing down on America’s Hometown.

“We did have a little glitch in the system that took us three or four minutes to figure out what was wrong,” said John Hark, Hannibal’s emergency management director. “It’s being looked into as what prevented them from sounding the first time.”

Mike Hall, director of Marion County 911, has a theory regarding what might have happened shortly after 4 p.m. Sunday.

“All 16 city storm sirens are activated over the air, through a single radio transmission. I reviewed the audio recording and discovered that there was radio traffic on another Hannibal police channel at the same time that the siren transmission was going out that may have interfered with some of the sirens in hearing the first transmission clearly,” he said. “A complete silent test off all sirens this morning (Monday) showed that everything was operating normally, which leads me to believe that yesterday’s situation was due to radio interference and we are looking into ways to prevent that from occurring in the future.”

According to Hark, the delay from when the warning was received and when the entire siren system sounded was not long.

“We got that rectified in a hurry,” he said. “(Marion County) 911 did an outstanding job. They were able to set them off and we set them off twice.”

Hall reports his agency was advised of the tornado warning at 4:05 p.m. and immediately activated the sirens.

“We were notified at 4:08 p.m. that only one or possibly two sirens were sounding,” he said. “We activated them several more times, from two different positions, and received confirmation that they were sounding citywide.

“We are at a disadvantage at 911 because we cannot hear the sirens from inside our building so we are dependent on someone, usually John Hark as it was in this case, to let us know whether they are sounding or not.”

Marion County 911 is not the only location from which sirens can be activated, according to Hall.

“They can also be set off from the Emergency Operations Center (on McMasters Avenue) and remotely by John Hark in his truck. So in the event that we have a situation where we are unable to activate them from 911, they can still be sounded through two other means,” he said.

Sunday’s siren-system problem came as a surprise.

“Previously it has operated pretty well,” said Hark. “We had one not work during the last test, but we got people in here who worked on it and got it fired up to where it would go.”

Sunday’s severe storms, which also prompted the activation of the siren system in Palmyra, according to Hark, spared the area.

“As far as any damage from storms yesterday, I’ve gotten no reports,” Hark said, describing the sky as appearing “very, very mean” late Sunday afternoon. “We truly lucked out that this thing moved on.”

According to the National Weather Service, 1.25 inch hail, was observed five miles west of Hannibal at 4:06 p.m.

Wall clouds were seen three miles east of Rensselaer (4:10 p.m.), two miles southeast of Palmyra (4:15 p.m.), west of Hannibal at Shinn Lane and Highway MM (4:18 p.m.), north of Frankford (4:20 p.m.) and just east of Hannibal Regional Hospital (4:41 p.m.)

The lone funnel cloud was reported by a storm chaser at 4:18 p.m. Located four miles west of Hannibal, the observer spotted a “rope funnel” that lasted only about a minute.

 Reach reporter Danny Henley at danny.henley@courierpost.com .