Table 1.
Summary of individual severe weather events and probability of an 8+ hour power outage co-occurring on the same county-day from 2018–2020.
Results are on the 1,657 counties with 3 years of reliable power outage data (1,799,208 total county-days). The individual severe weather events were not necessarily isolated events and could have also co-occurred with another severe weather event.
Fig 1.
Cumulative county-days of individual severe weather events co-occurring with an 8+ hour power outage from 2018–2020.
Results are on the 1,657 counties with 3 years of reliable power outage data (1,799,208 total county-days). The maps on the left share a common legend, and the maps on the right share a second common legend. White areas were excluded from the study because they lacked 3 years of reliable data. The individual severe weather events were not necessarily isolated events and could have also co-occurred with another severe weather event. Basemaps from the U.S. Census Bureau (https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.2018.html#list-tab-790442341).
Fig 2.
County-days during which a specific severe weather event co-occurred with an 8+ hour power outage over the total number of county-days for which any severe weather event co-occurred with a power outage, by state and year.
Results are on the 1,205 counties with 3 years of reliable power outage data and at least one co-occurring individual severe weather event and 8+ hour power outage (16,757 total county-days). Because we only included counties with 3 years of reliable data and at least one severe weather-power outage co-occurrence, some state-years lacked any events (e.g., North Dakota in 2018 and 2019).
Fig 3.
Cumulative days of severe weather types co-occurring with an 8+ hour outage by warm versus cool season in US counties from 2018–2020.
Results are on the 1,205 counties with 3 years of reliable power outage data and at least one co-occurring individual severe weather event and 8+ hour power outage (16,757 total county-days). Warm season refers to May–September, and cool season refers to October–April.
Fig 4.
Cumulative county-days of multiple (2+) simultaneous severe weather events that co-occurred with an 8+ hour power outage by US state from 2018–2020.
Results are on the 904 counties with 3 years of reliable power outage data and at least one co-occurring multiple simultaneous severe weather event and 8+ hour power outage (2,389 total county-days). The left-most column reports total state-level county-days of multiple simultaneous severe weather events co-occurring with an 8+ hour power outage. The first row reports total county-days for multiple simultaneous severe weather events co-occurring with an 8+ hour power outage. The x-axis is ordered from most (left) to least (right) frequent co-occurring simultaneous severe weather event types across all states.
Fig 5.
Frequency of multiple simultaneous severe weather event types that co-occurred with an 8+ hour power outage by US census region from 2018–2020.
Results are on the 904 counties with 3 years of reliable power outage data and at least one co-occurring multiple simultaneous severe weather event and 8+ hour power outage (2,389 total county-days). The perimeter of the circle is like a pie chart. The whole pie represents all county-outage-days exposed to multiple simultaneous severe weather events in our study. The colors around the perimeter indicate the proportion and count of county-outage-days exposed to each type of multiple simultaneous severe weather event. From the bottom right counter-clockwise, the perimeter highlighted in red indexes county-outage-days exposed to anomalous heat, purple indicates anomalous precipitation, pink indicates tropical cyclone, blue indicates snowfall, orange indicates wildfire, and navy indicates anomalous cold. The shaded arcs inside the circle indicate the prevalence of two severe weather events happening simultaneously with an 8+ hour outage. For multiple weather events with 3 types of severe weather co-occurring with an 8+ power outage, we included each unique pair as separate connections. As an example, a county-day with an 8+ hour outage and simultaneous anomalous heat, anomalous precipitation, and tropical cyclone would contribute to the count of county-outage-days for each of anomalous heat-anomalous precipitation, anomalous heat-tropical cyclone, and anomalous precipitation-tropical cyclone.
Table 2.
Summary of multiple simultaneous severe weather events and probability of an 8+ hour power outage co-occurring on the same county-day from 2018–2020.
Results are on the 1,657 counties with 3 years of reliable power outage data (1,799,208 total county-days). Proportion of county-days with multiple simultaneous severe weather events are relative to 1,799,208 county-days in the study. Only multiple simultaneous severe weather combinations observed in the data are presented.