At least four people were killed in Houston in the severe weather that slammed southeast Texas on Thursday, Mayor John Whitmire said in a news conference.

Two people were killed by fallen trees, another was killed by a downed crane, and the cause of the fourth death is unclear, Whitmire said just before 10:00 p.m. on Thursday, according to WFAA.

Saying that “downtown is a mess” after the city experienced winds at speeds over 100 mph, the mayor told non-essential workers to stay home on Friday.

“Stay at home tonight, do not go to work tomorrow unless you’re an essential worker. Stay home; take care of your children,” Whitmire said. “Our first responders will be working around the clock.”

Downed power lines and trees have caused extensive damage and traffic problems, with traffic lights being out across the city.

KHOU 11 Chief Meteorologist David Paul said the intense winds were like those of a hurricane. 

“If you lived through the core of these winds, you went through the equivalent of a Cat 1, if not a Cat 2 hurricane,” he said during a weather recap.

The eastern side of town’s water system was knocked off the power grid and has been running off of generators, and CenterPoint Energy reported that nearly 1 million users were left without power, WFAA reported.

Houston Independent School District canceled classes on Friday due to the emergency. 

Whitmire added that the city is in recovery mode, and that officials are opening up shelters for those in need. 

Acting Houston Police Chief Larry Satterwhite said that officers would be out patrolling throughout the night. 

Houston Fire Chief Samuel Peña warned of gas leaks in particular, saying his department has received many calls related to people detecting gas inside their homes. 

“He said if you smell gas inside your home, you need to leave immediately and call 911 from outside,” WFAA reported.