County annual report · FIPS 56019
2018 Johnson County, WY Power Outage Report
In 2018, customers in Johnson County, WY went without power for an average of 3.4 hours, a total of 18K customer-hours (Wyoming average 1.2 hours). That ranks 5th worst of 21 Wyoming counties and 1403rd of 2,798 nationally.
Compared with WY, the US and 2017
Coverage line is EAGLE-I's share of Wyoming customers tracked each year.
Biggest outages in Johnson County, 2018
The 10 outage episodes with the most customers out at once. Times are UTC.
| # | Started (UTC) | Ended (UTC) | Duration | Peak out | Customer-hours |
|---|---|---|---|---|---|
| 1 | October 23, 2018 17:15 | October 23, 2018 18:30 | 1h 15m | 3,638 | 921 |
| 2 | May 31, 2018 19:15 | June 1, 2018 04:30 | 9h 15m | 3,618 | 12K |
| 3 | January 6, 2018 05:00 | January 6, 2018 05:15 | 15m | 3,617 | 904 |
| 4 | March 23, 2018 00:00 | March 23, 2018 00:15 | 15m | 3,611 | 903 |
| 5 | February 4, 2018 14:15 | February 4, 2018 15:15 | 1h | 469 | 353 |
| 6 | September 20, 2018 10:00 | September 20, 2018 12:30 | 2h 30m | 328 | 401 |
| 7 | June 14, 2018 00:30 | June 14, 2018 02:00 | 1h 30m | 321 | 377 |
| 8 | July 27, 2018 09:00 | July 27, 2018 10:00 | 1h | 219 | 165 |
| 9 | November 18, 2018 17:30 | November 18, 2018 21:15 | 3h 45m | 211 | 739 |
| 10 | May 28, 2018 18:15 | May 29, 2018 01:00 | 6h 45m | 114 | 173 |
Outage episodes by size in 2018: 10 reached 100+ customers, 4 reached 1,000+ customers, 0 reached 10,000+ customers.
Utility reliability filed with the EIA
SAIDI (average outage time per customer) and SAIFI (average interruptions per customer) that utilities serving Johnson County reported on EIA Form 861 for 2018, or their most recent earlier filing. Utility-wide figures, not county-specific.
| Utility | EIA year | SAIDI | SAIFI | SAIDI excl. major events | SAIFI excl. major events |
|---|---|---|---|---|---|
| PacifiCorp | 2018 | 3.2 hrs | 1.62 | 2.0 hrs | 1.25 |
| Powder River Energy Corp | 2018 | 2.8 hrs | 1.52 | 2.8 hrs | 1.52 |
| Big Horn Rural Electric Co | 2018 | 4.0 hrs | 1.80 | - | - |
| Montana-Dakota Utilities Co | - | - | - | - | - |
| High Plains Power Inc | - | - | - | - | - |
About this data
- Outage figures come from DOE/ORNL EAGLE-I, which records customers out by county every 15 minutes. EAGLE-I tracked about 62% of Wyoming's customers in 2018; utilities it does not see are not counted.
- Hours per customer = outage customer-minutes ÷ 5,448 customers (ORNL modeled county customer count), including major storm days. It is comparable across counties but is not the SAIDI a utility files.
- An outage event is a continuous stretch with customers out; counts at 100, 1,000 and 10,000+ use its peak.
- Years loaded: 2015–2025. Johnson County has data for 2017–2025.
Cite this report
MassOutage (massoutage.com), Johnson County, WY annual power outage report, 2018, data as of Oct 3, 2026 02:41 UTC, sources: DOE EAGLE-I (https://eagle-i.doe.gov/); EAGLE-I modeled customer counts (MCC) (https://figshare.com/); EIA Form 861 (utility reliability) (https://www.eia.gov/electricity/data/eia861/). https://massoutage.com/reports/2018/wyoming/johnson-county