The first ice storm of 2016 hit Thursday.

But it wasn’t sleet. It was hail, so thick at times it looked like snow.

The surprise hailstorms busted in windshields from Fort Worth to Arlington, killed exotic birds at the Fort Worth Zoo and made for a chaotic Thursday morning commute.

The hailstones varied in size from blueberries to tennis balls.

“The main ingredient was instability in the atmosphere,” said National Weather Service meteorologist Matt Stalley. “We definitely had been advertising that there could be a few severe storms but they were more widespread than we anticipated.”

The storms rolled in early, with the first hail falling about 4 a.m. in Benbrook and eastern Parker County. A second wave of hail came a couple of hours later as commuters were on their way to work, forcing some drivers to stop under overpasses.

On what is historically their busiest week of the year, the Fort Worth Zoo delayed opening until 11:45 a.m. Thursday because of the damage caused by the hail.

“We got hit hard,” said Alexis Wilson, a zoo spokeswoman. “Worst of all, we actually lost some animals in our bird collection.”

Wilson said the final death count was five flamingos, a pelican and two smaller birds — an ibis and a baby black-neck swan cygnet.

She said others birds were being treated in the zoo’s hospital.

Wilson said golf-ball or larger sized hail pummeled the zoo around 6:30 a.m., damaging skylights, exhibit roofs and vehicles.

At MedStar headquarters in west Fort Worth, golf- to tennis-ball-size hail caused extensive damage to almost 50 vehicles and 11 ambulances were taken out of service because of busted windshields.

“We’ve contacted three windshield companies trying to get the ambulances repaired,” said Matt Zavadsky, MedStar spokesman. “We hope the ambulances are out just for a day.”

The Fort Worth Police Department’s West Division was damaged by the hail and heavy winds, as were other businesses in the area, including New Horizons Realtors, where large holes were punched in outside walls.

Fort Worth firefighters rescued a woman from her car on Hulen Street, near Interstate 30, where waters rose to waist-high about 7 a.m., Fire Department spokesman Kyle Clay said. Hail had clogged up the street’s storm drains, causing the water to rise.

Egg-size hail was measured in Benbrook and tennis-ball-size hail later fell in south Arlington, according to the National Weather Service in Fort Worth.

Three Arlington police cars had windshields destroyed at a substation near Lake Arlington.

Many of the same southwest Fort Worth and Benbrook neighborhoods hit Thursday had roofs replaced after receiving hail and wind damage in last year’s spring storms.

Mark Hanna, spokesman for the Insurance Council of Texas, said it was too early to tell how costly this hailstorm would be.

Hanna said that more than 6,000 auto claims had been filed in the first 12 hours after the storms.

Stalley, with the National Weather Service, said hailstorms are difficult to predict.

“That’s something you’re not going to know until the storms start to develop,” Stalley said.

The chance of storms will stick around for a while. There’s a 40 percent chance tonight and a 50 percent chance Friday and Friday night.