Power Out Map
– 0% of Lyman out 0 customers out in South Dakota

Power outage history

Lyman County South Dakota

5.5hours

without power for the average customer in a typical year, 2018–2025

16th most of 32 in South Dakota 17% below the national median

Worst outage on record Dec 26, 2020 13% of customers out · 90% back in 3.0 days
Hours without power, average customer per year 5.5h / yr State average 4.8 h · national median 6.6 h
Major outages a year 1.9 Peaks over 10% of customers or 50,000 customers
Typical time to restore 90% 2hours Median across major outages, from the peak
Longest single outage 6.1days Dec 23, 2020, over 1% of customers out
Outage hours on storm days 81% Share falling on days with a NOAA storm report here
Worst year 2020 23 hours without power, average customer
Electricity customers 2,969 ORNL customer model · 7 well-covered years

Every day since 2015

Eleven years, one night at a time

Each cell is a day. The brighter it is, the larger the share of Lyman's customers who were without power at that day's worst moment.

20152016201720182019202020212022202320242025
0%100% of customers out

Year by year

Hours in the dark, per customer

2020 was the worst well-recorded year, at 23 hours for the average customer. Hatched years have a thin record and are left out of the averages.

Lyman, hours without power per customer

LymanUS median countySouth Dakota average
0 10 20 30 2.2 ’19 23 ’20 3.7 ’21 4.0 ’22 2.0 ’23 1.5 ’24 2.0 ’25 US 6.6 SD 4.8

The record

The biggest outages since 2015

Ranked by customer-hours lost: customers out multiplied by how long they stayed out. Times are local.

Began Storm Peak out Share Lasted 90% restored Customer-hours
Dec 23, 2020 Windstorm 398 13% 6.1 d 3.0 d 58k
Mar 14, 2021 Winter storm 839 28% 25 h 4.5 h 4.4k
Jun 17, 2020 Thunderstorms 195 7% 10 h 8.5 h 1.8k
Oct 12, 2020 No storm report 628 21% 3.5 h 1.5 h 1.7k
Jul 18, 2023 Thunderstorms 430 14% 5.8 h 3.2 h 1.5k
Dec 14, 2022 Winter storm 76 3% 18 h – 1.3k
Jul 23, 2025 Thunderstorms 296 10% 11 h 4.8 h 1.3k
Aug 13, 2022 No storm report 187 6% 6.8 h 5.2 h 1.3k
Aug 5, 2022 Thunderstorms 330 11% 5.2 h 4.2 h 1.1k
Jun 13, 2022 Thunderstorms 426 14% 10 h 3.5 h 1.1k
Jul 28, 2019 No storm report 521 18% 2.2 h 2.0 h 1.1k
Jul 14, 2024 Thunderstorms 326 11% 5.5 h 4.2 h 1.1k

After the peak

How fast the lights come back

Each line is one major outage, from its peak. The amber line is the typical path.

0% 25% 50% 75% 100% peak+24h+48h+72h+96h half back by +4h 90% by +6h

When it happens

The outage clock

Customer-hours out by month (rings, January innermost) and local hour, 2018–2025.

00061218 Jan inside

What was happening

Weather behind the outages

Each outage is matched to NOAA storm reports for Lyman from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.

  • Windstorm 62%
  • No storm on record 19%
  • Thunderstorms 9.4%
  • Winter storm 9.2%

Who keeps the lights on

Utilities serving Lyman

As each utility reports to the Energy Information Administration for its whole South Dakota territory, not this county alone. Outage minutes include major storm days.

Utility Type Outage min / yr Excl. major storms Outages / yr Residential ¢/kWh Customers
West Central Electric Coop Inc SD 100 100 0.96 13.6 73k
Rosebud Electric Coop Inc Cooperative 141 78 0.77 11.9 4.9k
WAPA-- Western Area Power Administration Federal – – – – –

EIA Form 861, latest year each utility reported. Outage minutes are SAIDI, the yearly minutes the average customer goes without power; outages a year are SAIFI.

Next door

Neighbouring counties

Across South Dakota

Where it is darkest

Hours / yr64+

All South Dakota counties →

About these numbers

Notes

Outages come from the EAGLE-I record of utility outage maps collected every 15 minutes by Oak Ridge National Laboratory. Hours without power are customer-hours divided by the county's 2,969 electricity customers. Averages use well-covered years from 2018. Outages shorter than 15 minutes, and utilities that publish no outage map, are not in the record, so these figures understate the total. How every number is made →