Urban 'heat island' effect grows in Portland
Heat waves are a more regular occurrence, and some of the city's development is exacerbating the problem.
"We're just putting up buildings and not thinking about how we can better design them to reduce some of that reflectivity, some of that increase in thermal mass as we call it," said Vivek Shandas, a professor specializing in urban heat at Portland State University.
Shandas' research has allowed him to pinpoint down to a square mile the difference in heat throughout the city.
The general rule is the closer you are to a dense forest, the cooler it will be. Highways, concrete and a lack of trees heat things up.
On days in the 90s, the difference from one neighborhood to another can be 12 to 15 degrees, Shandas says.
Asphalt, in particular, is one of the biggest contributors to urban heat.
"Lightening the surfaces -- there are places around the world that we could also learn from," Shandas said. "Introducing some (vegetation) into the roads to make it a little bit more of a lighter shade of gray, so not to have the glare, but also to reflect some of the sunlight that comes down."
Portland Parks and Recreations boasts that some of its parks, such as Forest Park, Laurelhurst Park, and Columbia Park, are some of the coolest spots in the city.
That's why the bureau is encouraging further tree planting to help areas that don't get the benefits of a strong tree canopy.
"So there is climate change happening, and one of the things people can do in their own yard right away is keep the trees you have, keep them healthy," said Jenn Cairo, the Urban Forestry Division Manager.