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

Power outage history

Walworth County South Dakota

The outage record here is too thin for a reliable yearly average. Raw events are listed below.

Worst outage on record Oct 14, 2021 100% of customers out · 90% back in 3.2 hours
Hours without power, average customer per year –h / yr State average 4.8 h · national median 6.6 h
Major outages a year – Peaks over 10% of customers or 50,000 customers
Typical time to restore 90% 1hours Median across major outages, from the peak
Longest single outage 8hours Aug 6, 2019, over 1% of customers out
Outage hours on storm days 31% Share falling on days with a NOAA storm report here
Worst year –
Electricity customers 2,370 ORNL customer model · 0 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 Walworth'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

Walworth, hours without power per customer

WalworthUS median countySouth Dakota average
0 2 4 6 8 3.0 ’17 ’18 ’19 ’20 ’21 ’22 ’23 ’24 ’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
Oct 14, 2021 No storm report 2,370 100% 3.5 h 3.2 h 5.4k
Jun 4, 2017 No storm report 2,073 87% 2.5 h 12 min 2.7k
Jul 9, 2025 Thunderstorms 721 30% 4.5 h 3.5 h 2.6k
May 31, 2023 No storm report 771 33% 2.2 h 2.2 h 1.6k
Oct 17, 2019 No storm report 1,040 44% 1.8 h 1.8 h 1.6k
Sep 27, 2022 No storm report 2,021 85% 48 min 48 min 1.4k
Jul 4, 2018 Thunderstorms 343 14% 5.5 h 4.2 h 1.3k
Jun 1, 2022 No storm report 658 28% 1.5 h 1.5 h 984
Nov 14, 2017 No storm report 1,717 72% 2.5 h 2.2 h 912
Aug 6, 2019 Thunderstorms 115 5% 8.0 h – 849
Oct 3, 2022 No storm report 1,598 67% 2.2 h 1.2 h 816
Jun 7, 2020 Thunderstorms 112 5% 5.8 h – 622

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 +2h 90% by +4h

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 Walworth from twelve hours before it began to its peak. Matching shows coincidence, not proof of cause.

  • No storm on record 69%
  • Thunderstorms 24%
  • Ice storm 2.9%
  • Flooding 2.4%
  • Windstorm 0.8%

Who keeps the lights on

Utilities serving Walworth

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
Cam Wal Electric Coop, Inc SD – – – 12.5 40k
Montana-Dakota Utilities Co Investor Owned 212 206 2.62 13.0 6.3k
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

  • Dewey 3.8 h
  • Corson 2.5 h
  • Walworth (this county) – h

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 2,370 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 →