Whitmire said planning began on Thursday and will continue as the worst of the weather moves in Monday evening. He is urging caution for anyone not yet prepared for what is to come.
"Stay at home and leave our roads for our first responders," Whitmire said.
City leaders are encouraging Houstonians to be prepared to stay at home for the next 48 hours.
"Make sure that you know where the shut-off valve in your home is in case you have a catastrophe with a burst pipe," Randy Macchi with Public Works said.
Whitmire is urging caution for anyone not yet prepared for what is to come.
"Crews from public works today began treating critical overpasses, bridges, and other streets and corners throughout the city," Macchi said.
The pretreatment will help, but officials say it only raises the freezing temperature for any precipitation on the ground. Macchi said the weather will be so cold, icy roads are likely inevitable.
As the weather moves in, travel will become increasingly dangerous, and the public is asked to limit it as much as possible.
"I can work from home, so I am going to try to stay off the roads as much as possible," Teddy Branch, who is preparing to hunker down for the storm, said.
Part of your preparations beyond protecting plants and bringing your pets inside should include wrapping any exposed piping to keep them from freezing.
"Please make sure that you shut off your sprinkler systems and you drain them properly to prevent any sort of catastrophe and know where your water shutoff valve is," Macchi said.
Public works is advising people not to trickle their water faucets because it could severely impact water pressure across the city.
They do encourage residents to open cabinets under sinks to let warm air in.
Most importantly for the safety and efficiency of first responders, authorities emphasized the importance of staying off the roads.
"You're safer at home, and you put us sometimes in jeopardy trying to get on the roadway," Chief Noe Diaz with the Houston police said.
Whitmire is encouraging Houstonians to band together tonight and keep an eye on the community's most vulnerable.
"We'll get through this. We are a great city with great people, and we face things head-on and come out stronger," Whitmire said.