Substation explosion leaves most of Sioux Center without power
Nov 2015Published 5 Nov 2026Responsible editor: Chief Editor
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What happened
(1) On Saturday 21 November 2015, during a heavy snowstorm, the city's electric crew was restoring power to a small area of Sioux Center, Iowa, when equipment at the west electric substation failed. The failure caused a large surge of current, a loud bang, black smoke and a flash, and blue flames shot from nearby manholes. About 80 percent of the town lost power. The force of the blast ruptured a 12-inch water line, a gas service leak caused a small fire beside a house, and later that afternoon a wastewater plant generator started a roof fire.
The substation and equipment outside it were destroyed, along with distribution cables across a three- to four-block radius, some of which were reduced to ash or welded together. The utility's account says no one was lost. The source does not report injuries. Power was restored to the hospital within hours, to most of the town that afternoon, and to the whole town by about 2 a.m. the next day, roughly 18 hours after the event. A mobile substation was in place that night. This account is a retrospective opinion piece by the city's utility manager, published ten years later.
Contributing factors
The source does not state the root cause of the equipment failure. It describes the failure as happening during extreme cold and heavy snow, which had already kept city crews busy, and says some of the system was ageing. The utility says the cable damage reflected the very high current released by the surge.
Lessons learned
- Assess and renew ageing substation equipment, because weaknesses in a system can stay hidden until a fault stresses it.
- Design substations and feeders so that load can be switched to another substation and cable can be replaced without excavating whole routes.
- Agree mutual aid with neighbouring utilities in advance and ask for help early, since crews from other municipal utilities and retired staff supported the restoration.
- Keep electronic asset maps current so that records do not depend on paper files or individual memory.
More lessons on maintenance, inspection and ageing assets, electrical protection and isolation, emergency response and public communication, from every incident on the register.
Source
Published 2026-11-05. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.
