A squall line of thunderstorms Monday night whipped Central Texas with high winds and produced a tornado in Jarrell that overturned vehicles, tore roof pieces from homes and snapped tree limbs across northern Williamson County.

No residents in Jarrell were injured by the storm, Mayor Larry Bush said, but the city lost power from 8:45 p.m. Monday to 6 a.m. Tuesday.

The storm knocked down some power lines, he said. Jarrell school district classes were delayed for a few hours because of the power outage, he said.

Bush said he measured wind speeds of 62 mph at his home for about 15 to 20 minutes on Monday night when the storm hit.  

“We got some cattle trailers flipped over and a truck turned over on Interstate 35 and the driver was taken to the hospital with non-life-threatening injuries,” he said. “A lot of people are still out today trying to find trash cans or things that were not tied down to porches.”

The National Weather Service on Tuesday confirmed that the storms that hit Jarrell on Monday night produced a tornado. Meteorologists were assessing the damage to determine a strength rating for the twister, weather service meteorologist Jason Runyen told reporters Tuesday after flying over Williamson County in a helicopter with County Judge Bill Gravell.  

“What we saw from the air today, there were at least three dozen homes or businesses that sustained light to severe damage in Jarrell,” Gravell said. One house under construction was flattened, he said, adding that several roads had downed power lines that drivers needed to avoid.

The tornado first touched down south of Jarrell and west of Interstate 35, Runyen said. It then crossed I-35 and continued east and southeast.

The tornado was the third to hit northern Williamson County — the second in Jarrell — in the past seven months, said county Commissioner Russ Boles. The weather service said the first two tornadoes formed March 21 near Jarrell and April 12 near Florence.

“This is a community that has really been hit hard by the weather,” he said. "We are looking at another incident where hopefully no lives have been lost.”

Boles said emergency personnel were already on the ground right after the tornado hit looking for damage and any injuries.

Runyen said there was no particular reason why northern Williamson County had been hit by three tornadoes in the past seven months.

“It’s just the random luck of Mother Nature,” he said. 

Jarrell, the site of a tornado event that killed 27 people on May 27, 1997, does not have a siren system for possible tornadoes. Mayor Bush said that is because the city’s topography prevents the sound of the sirens from traveling very far. The city relies on emergency alerts from the county.  

“The Emergency Services District recommended we not put sirens in the city because it creates a false sense of security,” Bush said.  

Around 9:35 p.m. Monday, the National Weather Service received reports of possible tornado damage in the southbound lanes of I-35 in Jarrell. Power was knocked out across Williamson County from Round Rock to Florence.

Weather spotters reported "flipped-over empty livestock haulers and flatbed trailers. Additionally, a semi-truck was flipped on its side on I-35 southbound," according to forecasters, adding that a "large tree branch approximately 14 inches in diameter snapped halfway down the tree at Exit 275 in Jarrell."

An Emergency Services District fire station in Jarrell took heavy blows, suffering roof damage and having bay doors blown off by the storms, according to county emergency management officials. A preliminary estimate was that 50 homes also experienced roof damage, and multiple street signs were blown over.

Crews at the fire station in Jarrell posted on Facebook that although its "garage doors were blown off and about an 8x8 area of roof was also blown off," they assured the public that "we are still able to respond out of the station to calls for assistance."

The fire station windows on the roll-up doors were shattered by the storm because they faced north, which was the direction the wind came from, Bush said.  

A Jarrell fire captain was sent out in an Austin-Travis County EMS STAR Flight helicopter overnight "to survey the area to make sure there are no signs of citizens that may need help but are unable to call for assistance," fire crews said.

"Some empty horse trailers got blown into the service road near CR 313, and several trees ended up in roads across the area," they reported. "Some unoccupied new homes under construction sustained damage as well."

Similar reports of snapped tree limbs and broken power poles came from Granite Shoals in Burnet County, northwest of Austin.

About a half-hour later, around 10:05 p.m., the weather service received reports of high winds in San Marcos in southern Hays County. Spotters there reported "a measured wind gust of 60 mph at the intersection of West Centerpoint and Wonder World Drive."

The weather service said on Twitter that it plans to send teams to damaged areas.

"Our office will be surveying damage near Jarrell today associated with last night's storm. Please patient as we hope to have preliminary findings from the survey late today," forecasters said.

Heading into Monday, the Austin metro area had gotten a welcome soaking — its first rainfall of the month — a week earlier. But with only 0.73 inch of rain recorded at Camp Mabry, site of Austin's main weather station, the month remained on pace to be one of the driest Octobers ever.

For all the noise and bluster Monday night, Camp Mabry's rain gauges captured only 0.86 inch of rain. Combined with storms on Oct. 16-17, Austin's rainfall total for October to date is 1.59 inches, which is almost exactly half of the normal rainfall amount for this point in the month.

Before Monday, Austin had logged only 19.05 inches of rainfall since Jan. 1, a total that was about 10.4 inches below normal for this point in the year. Monday's storms merely shrunk the deficit to about 9.96 inches with a cumulative rainfall total of 19.91 inches.

The National Weather Service's extended outlook calls for sunshine and a brief return to stormy weather late Thursday.

"A surface cold front will swing through South-Central Texas (late Thursday), with scattered thunderstorms, some strong to severe possible Friday morning before quickly racing south and east towards East Texas Friday afternoon and evening," the weather service said in a bulletin Tuesday.