WIMBERLEY, Texas — Deadly severe weather over the long holiday weekend tested government alert and evacuation procedures, as officials scrambled to deal with storms and historic flooding that left more than a dozen people dead and a similar number missing.

Crews will resume searches today for the 11 people who have now been missing for three days in the small tourist town of Wimberley, where the usually calm Blanco River swelled to an ocean-like squall that crested three times above flood stage. In Houston, where nearly a foot of rain submerged roads and stranded hundreds of motorists, Mayor Annise Parker said two people who capsized in a boat that was helping with rescue efforts Tuesday have not been found.

At least 17 people were killed in the Memorial Day weekend storms in Texas and Oklahoma.

Authorities defended their warnings to residents ahead of the weather, which included alerts via phone and in person, but acknowledged challenges with reaching tourists and said a messaging system in Houston is still waiting for improvements.

“Nobody was saying, ‘Get out; get out; get out,”’ said Brenda Morton of Wimberley. “We’re pretty trained, so we were calculating. We knew the flood plain. People who were visiting or had summer homes, you have company from out of town, you don’t know. You don’t know when that instant is.”

Morton lives three houses down from a two-story vacation home authorities say was swept off its 10-foot pylons by a wall of water early Sunday morning with eight people inside, which included three children. The house slammed into a bridge after being carried downstream on the Blanco.

Authorities in surrounding Hays County said warnings included multiple cell phone alerts and calls to landlines. Some received in-person warnings to evacuate, but officials could not say whether those in the washed-away home talked to police.

“Law enforcement made notification along that street. Whether they made contact with somebody at their residence, I can’t say,” Hays County Emergency Management Coordinator Kharley Smith said.

Wimberley, a popular bed-and-breakfast getaway near Austin and surrounded by wine vineyards, thrives on weekends like Memorial Day. Some of the missing had homes in the area, but officials have acknowledged their electronic alerts may not reach tourists.

“Most definitely, most definitely that will certainly be part of our discussion,” Hays County Commissioner Will Conley said.