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When Infrastructure Confronts a Searing Heat Dome

Portland, Oregon’s crippled rail systems reveal how climate change sometimes outpaces infrastructure

4 min read

A thermometer reads 113 degrees Fahrenheit during a heat wave in Portland, Oregon, U.S. June 27, 2021.
A thermometer reads 113 degrees Fahrenheit during a heat wave in Portland, Oregon, U.S. June 27, 2021.

The “heat dome” that’s seared the U.S. Pacific Northwest and Western Canada since last week is afflicting both beings—human and otherwise—and infrastructure. I’ve been riding out this latest long-predicted signal of climate change in Victoria, British Columbia, where the temperature hit 39.7 ºC (103.6 ºF) yesterday—a day whose average high was (previously) 20.5 ºC. A small town in B.C.’s interior hit 47.5 ºC yesterday, breaking Canada’s longstanding temperature record recorded in Saskatchewan 80 years ago, for the second day in a row.

Many residents of coastal Oregon, Washington, and B.C. don’t have air conditioning, and they’re making do as best they can. Some are taking advantage of pop-up municipal cooling shelters. One friend outside Victoria has been giving her cats rides in her air-conditioned car, after they showed signs of heat stroke.

The region’s stretched infrastructure has gratefully held together so far, with two prominent exceptions—roads and rail.

Heat buckled road surfaces in Washington, as if Earth’s atmosphere is striking back against the petroleum-fuelled cars, trucks and buses that are the state’s #1 contributor to climate change. But the road damage caused only delays. Same goes for regional rail services under the heat dome, which cut speeds and lengthened commutes to avoid derailments from heat-distorted rails.

“We need to invest some thought into how we, as an agency, can become more climate resilient.”

Even the power grids have kept humming despite A.C. users like me setting new records for peak summer demand. Utilities in this region can take more. They are designed to handle higher winter peaks driven by inefficient electric baseboard heating.

However, infrastructure did grind to a halt in Portland—the Pacific Coast city most scorched by the heat dome. It smashed temperature records Saturday, Sunday, and Monday when it may have briefly hit 47.2 ºC (117 ºF). Which, as meteorolgist Eric Holthaus noted via Twitter, would be one of the hottest temperatures recorded worldwide in a major city).

High heat combined with electric current pushed metropolitan Portland’s streetcars and light rail systems past their limits.

“In case you're wondering why we're canceling service for the day, here's what the heat is doing to our power cables,” tweeted the PDX Streetcar system on Sunday, along with a photo of a seared power line. PDX Streetcar spokesperson Andrew Plambeck told me that cable warped, shifted and pressed up against superheated steel hardware on Portland’s Broadway Bridge.

Heat-induced stretching of cables posed the most widespread challenge to PDX Streetcar and regional transit operator TriMet’s MAX light-rail system. Overhead copper cables carrying 750 volts of direct current power both systems. As Portland crested above 110 ºF (43.3 ºC) on Sunday—the MAX system’s design limit—those copper cables expanded, stretched, and sagged.

Sagging lines can become entangled in the pantographs that reach up from train cars. They can even touch the train cars, creating a dangerous electric arc according to this video from French rail operator Groupe SNCF. So Portland’s operators eventually pulled their cars back to maintenance yards on Sunday, and kept them off the rails on Monday.

They returned to service Tuesday at reduced speeds. For PDX Streetcar it was to be a late start, Plambeck told me. “We had people out there trying to fix things today,” he said. “And we’ve pulled them back in because it’s simply too hot to work safely.”

Under normal conditions, pully-mounted counterweights maintain tension as temperatures rise and overhead cables expand. But on Sunday, the cables stretched so far that mechanism literally ran out of room. “Once temperatures reach a certain point the counterweight system reaches the ground. It has nowhere else to go,” TriMet spokesperson Tyler Graf told me.

TriMet tweaked its tensioning systems a few years ago to adapt its equipment to Portland’s steadily warming summers. That was back when Portland’s highest recorded temperature was still 41 ºC and, as Graf put it, exceeding 43 ºC was still “unthinkable.”

Graf couldn’t say whether the system could be tweaked further to survive the next heatwave of this magnitude. And it’s not just heat they have to worry about. In February Portland’s light rail systems shut down amidst the city’s worst ice storm, which coated overhead cables with more ice.

“We’re now coming to the conclusion that we need to invest some thought into how we, as an agency, can become more climate resilient,” said Graf. “Things we were worried about happening seem to be happening now.”

Being overtaken by climate change is a recurring theme today, according to energy experts. For decades climate scientists have been predicting more extreme weather events, and engineers and physicists have been calculating what that will mean for energy systems. Adaptation, meanwhile, has been comparatively slow.

As a trio of U.C. Berkeley researchers wrote in a San Francisco Chronicle op-ed last August: “Scientists have made more progress in developing climate data than society has made in understanding how to use it.”

Little has changed since then, especially in the electric power sector, according to Anna Brockway, a Ph.D. student in Berkeley’s Energy & Resources Group and coauthor of a 2020 review of grid planning for climate change in the journal Climate Risk Management. “The electricity sector is lagging behind,” Brockway told me by email.

That’s true even in California, wrote Brockway, which is a global leader in climate mitigation and is on the front lines of climate-driven drought and wildfires. She says that “climate adjustments” added into models that the state uses to predict future demand for electricity do not represent “the actual range of uncertainty predicted by climate scientists.”

As Brockway put it: “It seems that impacts from climate change are being felt more quickly than our decision-making processes are evolving.”

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