Designing neighborhoods to fend off heat waves

Next week could bring the hottest temperatures of the summer to Minnesota.

And heat waves are a health concern, especially in cities where buildings and pavement make things even hotter, and people don't always have access to fans and air conditioning.

A group of researchers and urban planners from across the country met this week to discuss how to design a neighborhood in Minneapolis to make it more resilient to heat waves.

Prospect Park's Witch's Hat water tower above University Avenue in Minneapolis overlooks two very different parts of the neighborhood. As part of the researchers' work through the University of Minnesota's Urban Climate Institute, John Carmody led participants on a tour of the neighborhood this week.

"If we walked up there a block, you'd see the elementary school, Pratt, and you'd also start to see these historic, attractive houses," he told the group, pointing out neighborhood landmarks.

But the researchers were focused on the other side of the neighborhood, across University Avenue, called Prospect North.

In one area, a backhoe dug through concrete debris. There's a working recycling facility but a lot of old, industrial structures that are no longer in use. Three new things stand out: A light rail station, a community garden and the massive Surly Brewing Company.

University of Minnesota architecture professor Tom Fisher said those new structures provide a hint of what this part of the neighborhood might be like in the future.

"This is sort of the old economy disappearing, the 19th- and 20th-century industrial economy gone, and the 21st-century economy coming in and taking over and figuring out what kind of space and facilities we need," he said.

A giant grain elevator towers above Fisher and the group. He said the researchers' goal is to design the neighborhood to be resilient to a changing climate. The land around it has plenty of weeds but few trees — a concern during the summer.

Minnesota may be one of the coldest states in the country, but folks here know the Twin Cities can feel just as hot as cities in the South.

Researchers also know that temperatures within the Twin Cities' urban core — especially Minneapolis — run 2 to 4 degrees hotter than elsewhere.

Tracy Twine is a climate scientist at the University of Minnesota who studies these urban heat islands, which are caused by multi-lane highways, buildings and parking lots.

"Those properties are absorbing radiation from the sun differently, and it really becomes the biggest effect at night, where the urban areas hold onto that heat," Twine said.

That takes a toll on the human body, especially if the heat wave lasts several days. "Night is when the body needs that cool-down to recover," Twine said. "So you know there will be more deaths and illnesses a couple days into a heat event when people have not been able to recover from that heat."

Twine and university climate scientist Peter Snyder oversee a network of temperature monitors throughout the Twin Cities that will soon have five years' worth of data. Snyder said a warming climate could exacerbate the urban heat island effect in the future.

"What we're seeing now with the warming, where it's occurring, gives us a reason to start studying how we might mitigate that in the future," Snyder said.

A day after touring the Prospect North site in Minneapolis, across the street from the Witch's Hat tower, researchers and planners pored over giant maps of the neighborhood. They made lists and plastered Post-It notes all over the maps with ideas of how to design the community.

One popular idea was using alternative roofs to keep temperatures down in the summer. Researchers discussed how to do that without losing needed energy in the winter.

Brian Stone, a professor at Georgia Tech University in Atlanta who studies how cities adapt to heat waves, participated in the exercise.

"It's the kind of issue that we might think would be most commonly on the radar of cities in the Southwest like Phoenix, and that's true, but the greatest vulnerability tends to be in cities like Minneapolis and St. Paul where the population is not well acclimated to heat," Stone said.

Meanwhile, health officials are on guard for next week's potential heat wave and will be working to spread the word on how to keep cool.