(CNN) -- At 18, Alyssa Renee Ramirez's accomplishments read like a list of many teenagers' dreams: Homecoming queen. Student council president. Star athlete.
Her storied high school career was nearing an end with one final rite of passage -- her senior prom. But as Ramirez was driving home from prom over the weekend, her car was swept away by floodwater in Texas, ending her short but illustrious life.
"She did the right things," her aunt Roberta Ramirez told CNN affiliate WOAI. "She called 911. She called her father, but it was just too much and too quick."
Ramirez is one of six people who died in Texas and Oklahoma in the past four days as epic rainfall and flooding wracked both states.
And there's more dangerous weather on the way.
Houston, Louisiana under the gun
Now, the densely populated Houston area is getting pummeled.
About 5 to 8 inches of rain have fallen in less than a day, Houston emergency management coordinator Rick Flanagan said Tuesday morning. More than 80,000 electricity customers in the area were without power Tuesday morning.
The flooding has turned roads into ponds, but poor visibility has caused some drivers to travel though floodwater anyway, Flanagan said.
In just two hours, Houston's fire department received 150 requests for people needing help, he said. And with many of the bayous about to crest, any additional rainfall could flood more streets and homes.
The National Weather Service said the Houston-area counties of Harris and Fort Bend are getting thrashed with more rain Tuesday.
"This continues to be an extremely dangerous and life-threatening situation," the National Weather Service said. "Do not attempt to travel unless you are fleeing an area subject to flooding or under an evacuation order."
CNN meteorologist Pedram Javaheri said Louisiana is up next.
Over the next few days, the storm will move east and dump 4 to 6 inches of rain over central and southern Louisiana.
"This is a long duration event," he said.
12 people still missing
In Texas, authorities are still scrambling to find 12 people missing in Hays County, San Marcos Emergency Coordinator Ken Bell said.
Complicating search efforts: The county still has Internet problems, and cell phone networks are overwhelmed.
"People outside our community know more about what's going on than people inside our community," Bell said.
Up to 400 homes have washed away in Hays County, not far from the Texas capital of Austin.
"We do have whole streets that have maybe one or two houses left on them," emergency management coordinator Kharley Smith said. "The rest are just slabs."
Victims include firefighter
Of the six fatalities, four people died in Oklahoma.
In Tulsa, a woman died after her car hydroplaned Saturday. In Claremore, a firefighter got swept into a storm drain while attempting a high-water rescue Sunday. And in Sapulpa, a 37-year-old man died in the severe weather Monday, but the exact circumstances were not yet clear.
CNN affiliate KXII said the fourth victim, Sandra Callicoat Swinney, 48, was killed when a tornado touched down in the community of Blue.
The other two deaths were in Texas. In addition to Ramiriez's death in Devine, one person died in San Marcos, officials said.
13 killed in Mexico
The same storm system that tormented Texas also killed 13 people in Mexico.
In six seconds, a tornado ripped through the border city of Ciudad Acuña, Mexico, with a ferocity that officials said hasn't been witnessed in more than 100 years.
The 13 killed included three children, Acuña Mayor Evaristo Lenin Perez said. Another 200 were injured.
Acuña is a historic border city that people outside of Mexico know as the setting for Robert Rodriguez's films "El Mariachi" and "Desperado," and George Strait's song, "Blame it on Mexico."
Grappling with the disaster
Devine High School seniors will now have to celebrate their graduation June 5 without their homecoming queen and student council president.
But classmates say they'll remember Ramirez, an aspiring optometrist, for her positive attitude and magnetic personality.
"Every time you walk by her, she was smiling," said classmate Shay Agbert told WOAI. "Lightened up everybody's mood."