-- The devastation left in coastal U.S. cities after Hurricanes Harvey and Irma has many wondering if multiple, high-category hurricanes making landfall will be a "new normal" moving forward, leaving questions about how coastal cities can prepare for future storms.
Though scientists are reluctant to say hurricanes will be more frequent moving forward, two experts who spoke to ABC News were confident that the ones that do come will likely be serious.
Worries about increasing frequency are not new and the future of hurricane seasons is difficult to predict.
"In 2005, we had a flurry of storms and Florida got hit by a number of hurricanes," Rob Young, a coastal geologist from the program for the study of developed shorelines at Western Carolina University, told ABC News. "We wondered if it was the new normal then, and then it got quiet for about 10 years."
"I think that it would be a mistake to say that the new normal is that we have three named storms [Hurricanes Irma, Katia and Jose] churning around at the same time and making landfall in the U.S.," Young said. "That would be stretching it.”
Brenda Ekwurzel, the director of climate science at the Union of Concerned Scientists, echoed that sentiment.
"The past isn’t necessarily a guide," she said, adding that she bristled at the prospect of deeming storms like this summer as a new normal. "We're going into unchartered waters."
The strength of future hurricanes, however, is definitely a concern that scientists want to address.
Ekwurzel said humans may have skewed the probabilities on hurricane patterns.
"We've increased the odds now that when a hurricane ... is headed to make landfall in the U.S., climate change has loaded the dice and increased the odds that it will land as a major hurricane -- Category 3 or 4 or 5."
With those future, strong storms in mind, some cities are working on preventative measures. But the trade-offs that come with some of those ideas may be costly, in many ways.
Young pointed to a new study underway in Boston to assess whether a hurricane barrier to protect the city could be built. The projected price tag is estimated around $10 billion.
Boston mayor Marty Walsh defended the study after the high cost raised eyebrows.
"If we got hit with Harvey we are talking $50 or $60 billion in damage," Walsh said during a Aug. 30 interview on Boston Herald Radio. "Does that $10 billion look crazy anymore?"
Reflecting on the possible plan in Boston, Young said that there could also be environmental costs to installing massive barriers.
"This option of incredibly expensive, massive engineering is one way to try to protect some urban areas from storms," he said. "But, we probably can’t afford to protect everything that way and, if we did, the environmental impacts are likely to be significant."
Young believes one of the solutions is to create less infrastructure instead of more, even in areas that are under reconstruction.
"The first and most simple step would be let’s not create any more problems by putting additional infrastructure in those [vulnerable] areas," he said. "Let’s not rebuild non critical infrastructure in those areas."
A shift in urban planning in hurricane zones that were previously damaged could help, since creating barriers along the entire U.S. coastline is also not realistic.
"In order to spend the money wisely, we really need some kind of national vision, some kind of big picture plan," Young said. "The problem right now is we have no national vision, or plan or guidance."
While history can’t be the absolute guide, destructive hurricanes can serve as instigators setting change in motion like building codes and urban planning measures.
"Hurricane Andrew woke up a lot of people and they did a lot of planning that helped in Hurricane Irma," Ekwurzel told ABC News.
Scientists and technology have become better and faster at understanding the movement of hurricanes, which is a positive step.
"[The National Oceanic and Atmospheric Association] and others have gotten much better at learning where these hurricanes land. Science investment is paying off," she said.
“I think we are saving more lives as a result," Ekwurzel said. "I would like us to do even better.”