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

Power outage history

Grant County South Dakota

26hours

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

2nd most of 32 in South Dakota 3.9× the national median

Worst outage on record May 20, 2021 48% of customers out · 90% back in 6.4 days
Hours without power, average customer per year 26h / yr State average 4.8 h · national median 6.6 h
Major outages a year 3.0 Peaks over 10% of customers or 50,000 customers
Typical time to restore 90% 6hours Median across major outages, from the peak
Longest single outage 6.4days May 20, 2021, over 1% of customers out
Outage hours on storm days 5% Share falling on days with a NOAA storm report here
Worst year 2021 3.2 days without power, average customer
Electricity customers 3,124 ORNL customer model · 5 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 Grant'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

2021 was the worst well-recorded year, at 3.2 days for the average customer. Hatched years have a thin record and are left out of the averages.

Grant, hours without power per customer

GrantUS median countySouth Dakota average
0 20 40 60 80 100 ’19 ’20 77 ’21 43 ’22 0.9 ’23 2.5 ’24 5.1 ’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
May 20, 2021 No storm report 1,490 48% 6.4 d 6.4 d 228k
Jul 19, 2022 No storm report 1,495 48% 2.4 d 6.2 h 85k
Jan 30, 2022 No storm report 577 18% 2.2 d 2.2 d 30k
Sep 4, 2021 No storm report 577 18% 19 h 19 h 11k
May 12, 2022 Tornadoes 752 24% 14 h 11 h 6.6k
Jun 20, 2022 Thunderstorms 490 16% 12 h 1.0 h 5.6k
Aug 12, 2025 No storm report 1,910 61% 2.8 h 2.5 h 5.0k
May 30, 2022 Tornadoes 1,377 44% 6.8 h 6.2 h 3.2k
May 15, 2025 Windstorm 445 14% 6.2 h 7.2 h 1.9k
Apr 7, 2025 No storm report 1,916 61% 1.0 h 6.5 h 1.8k
Aug 21, 2024 No storm report 1,674 54% 48 min 30 min 1.2k
Jun 17, 2025 No storm report 144 5% 8.0 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 +8h

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

  • No storm on record 95%
  • Tornadoes 2.5%
  • Thunderstorms 1.5%
  • Windstorm 0.7%

Who keeps the lights on

Utilities serving Grant

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
Codington-Clark Elec Coop, Inc SD – – – 9.4 87k
H-D Electric Coop Inc SD 60 60 1.02 11.1 67k
Whetstone Valley Elec Coop Inc SD 56 56 1.62 12.1 60k
Otter Tail Power Co Investor Owned 191 189 1.73 11.4 9.1k
Montana-Dakota Utilities Co Investor Owned 212 206 2.62 13.0 6.3k
City of Big Stone City SD – – – – 3.5k
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 3,124 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 →