How many Seattle homes could be underwater by 2100? [Updated]

Update: Many readers have pointed out that this research adds a blanket six feet to sea levels without taking the Ballard Locks into account. “[National Oceanic and Atmospheric Administration] data doesn’t account for infrastructure already in place, so this is a limitation of US government data,” said a Zillow spokesperson.

We’ve integrated this into the article.

Extreme changes in weather, as we’ve seen recently during Hurricanes Harvey, Irma, and Maria, tend to hit low-income communities the hardest. Global climate change disproportionately affects minority and low-income communities. But how will that look in Seattle?

A new report by Zillow shows how many Seattle homes at risk for flooding if sea levels were to rise six feet—about midway between low and extreme estimates for sea level in the year 2100—and breaks it down along class lines. Out of more than 5,000 homes in the Seattle metropolitan area that are affected, 24.7 percent of them are among the lowest-value homes. That’s compared to 12 percent of mid-level homes.

Courtesy of Zillow

That doesn’t mean high-end homes are immune; they actually make up the majority of homes at risk for flooding. Zillow found that 63.3 percent of high-end homes would be made vulnerable. But, Zillow notes, low-income homeowners tend to have more of their wealth tied up in their home’s value than high earners.

In Seattle proper alone, Zillow says nearly 1,600 homes are at risk for flooding—although their research, as many astute Curbed Seattle readers have pointed out, doesn’t take into account the Ballard Locks, which separates Seattle’s lakes from the sea, so lakefront homes may not be as in jeopardy as the map implies. Zillow chalks this up to limitations from the government data that’s available.

Nearly 30 percent are lower-value homes—many of them clustered in South Park and the Rainier Valley, although the latter are along Lake Washington.

Still, less than 1 percent of all Seattle homes are at a flood risk with a six-foot rise in sea level. Most vulnerable in the metro area is Fox Island, which would find 7.5 percent of its homes underwater, followed by Fife and Stanwood.

Tacoma is fairly resilient. Only 0.4 percent of its homes would be vulnerable to flooding, and 96 percent of them are higher-end homes—more likely to be able to purchase safety upgrades.

The Seattle metropolitan area is in decent shape compared to other cities, though. In Miami, nearly a quarter of all homes would be vulnerable to flooding.

This article has been updated to account for the Ballard Locks, which appear to not be taken into account in Zillow’s research. We’ve reached out to Zillow for comment but have not heard back.

• Climate Change and Homes: Who Would Lose the Most to a Rising Tide? [Zillow]