Much of the conversation around climate change centers on extreme events—longer, more intense droughts; higher temperatures; intensive hurricanes. But another phenomenon is catching the attention of scientists, as well as the building industry: “Weather whiplash” is the more sudden shift in extremes of temperature and precipitation.
“These wild swings from one weather extreme to another are symptomatic of a phenomenon, variously known as ‘climate whiplash’ or ‘weather whiplash,’ that scientists say is likely to increase as the world warms,” wrote Jim Robbins in Yale Environment 360 last November. “The intensity of wildfires these days in places like California are a symptom of climate change, experts say, but the whiplash effect poses a different set of problems for humans and natural systems. Researchers project that by the end of this century, the frequency of these abrupt transitions between wet and dry will increase by 25% in Northern California and as much as double in Southern California if greenhouse gases continue to increase.”
And just as extreme weather events threaten the resilience of the built environment, so does weather whiplash, in both similar and unique ways. The threat is one that experts say architects need to be thinking about to ensure the durability and longevity of their buildings, even in regions of the country they may not have had to consider before.
“With climate change, there’s an understanding that there’s a potential for [extremes] to happen,” says Nick Rajkovic, assistant professor at the University at Buffalo. “And it’s certainly going to stress our infrastructure and our buildings pretty significantly.”
The Challenges of Weather Whiplash on Buildings
As an architect and a former program director at State Farm Insurance, Rose Grant, aia, has dedicated much of her career to studying disaster response and resiliency. “When we see extreme temperature swings in a 24-hour period, we have to wonder, ‘Are the materials we’ve selected for our buildings going to respond quickly enough?’ ” she says. “So we need to look at things we already do, but maybe with a different amount of concern.”
Among the risks are rapid freeze-thaw cycles caused by significant temperature swings. They can lead to the excessive expansion and contraction that causes expansion joints to fail, leads to cracks in foundations, and heaves sidewalks, all in much quicker cycles than one would typically plan for in the life span of a traditional structure.
The cycles also can create an issue with snowmelt. For buildings with low-slope roofs, a rapid freeze-melting-refreeze could cause frozen water to block drainage, thereby leading to ponding water and potential roof collapse.
Such occurrences may be even more jarring for areas where such extremes were previously a once-in-a-generation event. On a visit to Memphis, Tenn., for instance, Grant witnessed frozen water lines caused by a sudden drop in temperature that wasn’t anticipated for the typical design of buildings there. Other areas have experienced similar phenomena with the arrival of the polar vortex, which is increasingly pushing farther and farther south; where once freeze events happened every couple of decades, they’re now taking place more frequently and for longer periods, she notes.
On the opposite end of the spectrum is drought—not only the extended periods of drought we’ve been seeing in recent years, such as in California, but a situation known as “flash droughts,” Grant explains, or the rapid onset of a drought. A drought followed by lots of rain can also overwhelm systems such as subsurface dewatering systems and sump pumps, as well as sanitary and zone water systems, which can cause water backups into buildings.
How to Prepare
“The difficult part is that the climate is changing in ways we can’t always predict,” Grant says. “We don’t necessarily know what the absolute metrics are that we need to design our buildings for. It’s very difficult for designers.”
First and foremost, Grant recommends that architects pay attention to climate science and focus on education. Managing weather whiplash means thinking through worst-case scenarios and understanding the limitations of building materials beyond the norms within which they’re typically specified.
And since most codes and standards are written from the perspective of history, they may not address the new extremes. Consider flood maps, Grant says. “Flood maps are based on past events. But that doesn’t necessarily tell us what might happen in the future. So is a design to 1 foot higher than predicted good enough or does it need to be three or five?”
Nick Rajkovich, assistant professor at the University of Buffalo, says that architects should try to understand these potential extremes as they apply to the local level, at least as much as is possible. “Think about how buildings shed water or how over time we might see the ground freeze-thaw in different ways,” he advises. “We’re not going to have perfect predictions.”
One resource for architects was developed by Rajkovich’s team for the New York State Energy Research and Development Authority. “Adapting Buildings for a Changing Climate” includes eight reports, six webinars, and four fact sheets available for free download.
Just as important, existing buildings must be considered. “I think there is a tremendous opportunity for architects to develop expertise in retrofits and mitigation strategy that they can utilize with clients when there are existing buildings involved,” Grant says.