Seeing footage of families being evacuated from Houston neighborhoods by boat makes it hard not to wonder: What if it happened here? Could people be evacuated in time? City and state officials are looking at Texas and asking those same questions.

Boston Mayor Marty Walsh says there’s no question what we’d have to do if it happened here.

“If a storm like that hit Boston or Superstorm Sandy hit Boston — Harvey, Sandy whichever one it is — you have to evacuate," he said. "Evacuate the city.”  

And it’s a scary thing to picture.

“How do you get the North End evacuated? How do you get South Boston evacuated? How do you evacuate East Boston, parts of Dorchester with the Neponset River?” Walsh asked.

“We've been continuously updating our evacuation plans,” said Austin Blackmon, the city's chief of environment, energy and open space. He said Boston is working with state and national authorities to develop the plan. “So, making sure that we understand what our transportation and evacuation routes are, how we need to have those staffed, how we make sure that we get people out of danger,” he said.

One focus would be to reach the city’s most vulnerable residents, according to the city’s chief resilience officer, Dr. Atyia Martin. “So when you think about communications, you’re also thinking about folks who are immigrants who don’t speak English or don’t speak English well," she said. "Or people who might have other ... trust issues with government and receiving information.”

And of course it’s not just Boston that may need evacuation. “We have, you know, 70-plus coastal communities, and every one of them has areas that are susceptible to life-threatening storm surge,” said Kurt Schwartz, director of the Massachusetts Emergency Management Agency (MEMA).

“The key to a successful evacuation in advance of a hurricane is calling for the evacuation sufficiently in advance of the arrival of the storm,” he said. That’s probably the trickiest part of ordering an evacuation — officials would need to make that call before they could even be sure if the storm was really going to hit the area. They’ve created maps ranking the spots most likely to flood, to prioritize those evacuation orders.

You can find them online here at MEMA’s website. Around Boston, the red parts of the map, which are most vulnerable, include Chelsea, East Boston, Winthrop, Dorchester, Quincy and Medford. And pretty much the whole coasts of the North and South Shores are red, as well as the coasts on both sides of Cape Cod.

“If you live in a coastal community or in a community that has waterways that open up to the ocean, you need to know whether you live in a hurricane evacuation zone,” he said.

Schwartz says it’s essential that people in those zones have a plan, and have enough food and supplies to keep going for at least three days.

As for evacuating by car, it could be a challenge in a state where there’s gridlock traffic under the best of circumstances, and very unclear evacuation route signage. Schwartz acknowledged the difficulty, but said police would be at traffic points along the evacuation route to help keep cars moving.

But a lot of people don’t have cars. What about them?

“The city will designate places where people may walk to and get on buses and be transported by buses to reception centers and then on to shelters,” Schwartz said.

The state’s hurricane evacuation plan is based on a scenario of coastal flooding. But Schwartz points out that’s not what happened in Houston. There, the storm just parked itself over the area, and it’s the rain that was the problem.

“There is little doubt that if we had a storm system that dumped 20, 40, 50 inches of rain in Massachusetts, we would have widespread massive flooding just like Texas is experiencing,” he said. And with that, he says, we’d have all the same challenges they’re seeing in Houston.

“Even if we had evacuated people out of the coastal evacuation zones, the flooding in other areas would be massive, destructive and life-threatening,” he said.

Schwartz said the state does have plans for inland flooding, but up to now, they haven’t planned for a storm that dumps 50 inches of rain on our region. In fact, he doesn’t think anyone in the country planned for something like that. Now, he says, officials may have to rethink what he calls the "thresholds" of the state’s emergency evacuation plan.