Exploring the link between extreme weather and major power outages

A recent study out of the United States has investigated the relationship between severe weather events and power outages. Understanding this relationship is crucial for developing disaster response plans, especially as the climate changes.

Led by Vivian Do from Columbia University Mailman School of Public Health, the study has been published in the open-access journal PLOS Climate.¹

As in Australia, it’s common for severe weather events in the US to be accompanied by large-scale power outages. These combined events can lead to major economic costs and health risks, with loss of power disrupting medical equipment, heating or air conditioning, and other important systems. As severe weather events increase in severity and frequency due to climate change, understanding the patterns and distribution of these outages is critical for community preparation and resource allocation.

Along with her colleagues, first author Do, a PhD candidate in environmental health sciences, compiled data from 2018–2020 on severe weather events (including rain, snow, heat, cold, cyclones and wildfire) and large-scale power outages lasting eight hours or more for over 1600 counties across the US.

The researchers noted that, while previous studies had examined individual severe weather events (eg, heatwaves) and focused on large outages in metropolitan areas, Do and her colleagues described nationwide spatiotemporal patterns of individual (eg, tropical cyclone alone) AND simultaneous (eg, tropical cyclone + anomalous heat) severe weather events co-occurring with 8+ hour outages. The team used hourly county-level PowerOutage.us data from 2018–2020 to define 8+ hour outages as whenever the daily proportion of customers without power was ≥0.1% for ≥8 continuous hours.

The data revealed that nearly 75% of the 1600 counties experienced major power outages alongside severe weather events during the three-year period; and over 50% of counties experienced outages alongside multiple simultaneous weather events.

Outages most commonly occurred alongside severe precipitation and heat, with precipitation-associated outages more common in the Northeast US and heat-associated outages more common in the Southeast. The study also found that co-occurring outages and wildfires became increasingly common along the West Coast from 2018 to 2020.

Multiple (2+) simultaneous severe weather events appeared to drastically increase the chances of a power outage. In New York, for example, when compared to days with no severe weather, 8+ hour outages were 9 times more prevalent during extreme heat alone, 30 times more prevalent during precipitation, and a whopping 391 times more prevalent during a heat and heavy precipitation event.² This trend was also observed nationally.

One limitation of the study was a lack of reliable data for some US counties, so the researchers didn’t have much information about regions such as the Southwest and Mountain West.

Do and her colleagues suggested that further research providing additional data, along with simulations of severe weather combinations in different locations, will be useful for developing mitigation and response tactics.

“Power outages frequently co-occur with severe weather events like heavy precipitation, tropical cyclones or multiple severe weather events simultaneously,” Do explained.

“Understanding patterns of where and when power outages and severe weather events co-occur is crucial for informing strategies to minimise societal consequences, especially as the electrical grid ages and climate change drives more severe weather events.”

The team’s research was funded by United States’ National Institute for Environmental Health Sciences, the National Institute on Aging, and the National Heart, Lung and Blood Institute grant.

_{1. Additional authors included Nina Flores and Heather McBrien at Columbia Mailman; Lauren B. Wilner and Joan A. Casey at the University of Washington, Seattle; and Alexander J. Northrop at The Children’s Hospital of Philadelphia and Ichan School of Medicine in New York.}

_{2. Flores NM, Northrop AJ, Do V, Gordon M, Jiang Y, Rudolph KE, et al. Powerless in the storm: Severe weather-driven power outages in New York State, 2017–2020. PLOS Climate. 2024 May 1. https://journals.plos.org/climate/article?id=10.1371/journal.pclm.0000364}

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