Houston storm: At least five killed, more than 600,000 without power

(HOUSTON) — At least five people were killed when a powerful storm tore through Houston on Thursday night, officials said.

Fallen trees appeared to cause at least two of the deaths, according to officials.

Straight-line winds peaked at around 100 mph in downtown Houston, and residents told ABC News the winds sounded like a freight train.

The winds were so powerful, Harris County Judge Lina Hidalgo said they were comparable to Hurricane Alicia in 1983.

One tornado was confirmed near Cypress, officials said.

Houston Mayor John Whitmire urged residents to stay home Friday following the “exceptionally” strong storm, noting 2,500 traffic lights are not functioning.

Houston schools closed on Friday and more than 600,000 customers remain without power.

For some, the power could be out for weeks, Hidalgo said.

The mayor said Houston is in “recovery mode.”

“Please … stay away from downtown — it’s dangerous. There’s broken glass in every direction,” Whitmire said.

White House press secretary Karine Jean-Pierre said the Federal Emergency Management Agency is working with state and local counterparts and is “ready to provide federal assistance as needed.”

She said the White House is “praying for four people who tragically lost their lives in Houston” and “also thinking of those who were injured and the communities that were affected by this extreme weather.”

The intense winds came after a rare “high risk” warning for flash flooding was issued in Texas and Louisiana, with the states bracing for up to 9 inches of rain in 24 hours.

“The high risk area has seen over 600% of their normal rainfall for the past two weeks alone,” the National Oceanic and Atmospheric Administration warned, and the flash flooding could be life-threatening.

“High risk” days account for just 4% of days, but they are responsible for more than one-third of flooding deaths, according to the Weather Prediction Center.

The storm in Houston is now over, allowing residents to begin to cleaning up on Friday.

The severe weather threat has now moved east, with flood watches in effect from Louisiana to the Florida Panhandle. The heaviest rain is expected Friday and this weekend in parts of southern Mississippi, Alabama and the western Florida Panhandle.

Jean-Pierre said Friday, “We continue to monitor the storm’s path as it moves east, and more severe weather is likely across the Gulf Coast today. Residents in the affected area as well as those in the path of the storm should heed warnings from state and local officials.”

ABC News’ Mireya Villarreal, Justin Ryan Gomez and Daniel Amarante contributed to this report.