Rescue workers in Nebraska searched the Missouri River on Wednesday for three people believed to have drowned after going into the water on Tuesday evening, fire officials said.

One of the three is an 11-year-old girl and the other two are 18-year-old women, said Coby Werner, the fire battalion chief for the Omaha Fire Department. Two pairs of shoes that matched witnesses’ description of what they were wearing were found in the river on Tuesday night, he said.

Rescue crews from several agencies, including the Douglas County Sheriff’s Office, battled windy conditions during their search on Wednesday, Chief Werner said.

The search for the girls began after a bystander found a 13-year-old girl on the riverbank in N.P. Dodge Park just before 6 p.m. on Tuesday. The girl, who was described as “hysterical,” told the bystander that she had gone into the water with the three others from a spot where they had been fishing, Chief Werner said. The current “kind of carried them downstream a little bit,” he said, and the three missing people went under water and did not resurface. The chief said the girls were related, but it was unclear how.

The Missouri River has a “pretty good current,” Chief Werner said, calling it a “dangerous body of the water.” Its depth in that area is as deep as 15 feet, he said, with a temperature of 45 degrees — enough to make someone “hypothermic within a matter of minutes.”

Chief Werner said rescue workers had broken the river into different quadrants and sections, with “over eight boats from multiple different agencies out here all day.”

He described the river there as murky and muddy, with rocks, logs and other debris that can occasionally flow through. According to the local television station KMTV, “Flooding is a familiar struggle at N.P. Dodge Park.”

It’s early in the year for water rescues, according to Chief Werner. He said these typically “start a little bit more once you get to the latter half of May and then throughout the summer.”

Chief Werner said that when it comes to a drowning or a water rescue, the first hour that someone is in the water is the “golden hour.”

“After that we slowly kind of transition into a recovery mode.” he said. As of Wednesday morning, he added, rescue crews were in “recovery mode.”

That “doesn’t mean we’re not still doing everything we can to search,” Chief Werner said, but it “means we’re slowing down a little bit and doing more of a methodical search.”