August 12, 2026
October 7, 2026
Prior To Major Event
1. Did the distributor have any prior warning that the Major Event would occur?
No.
Please Provide Additional Comments:
Hydro Ottawa maintained standard monitoring following Environment Canada’s yellow weather watch, which indicated the potential for moderate weather hazards; however the actual event exceeded the forecasted impact level of the weather watch.
2. If the distributor did have prior warning, did the distributor arrange to have extra employees on duty or on standby prior to the Major Event beginning?
No.
If yes, please provide a brief description of the arrangements, or explain why extra employees were not arranged:
Because there was no advance indication that the severe weather watch would escalate into a Major Event, Hydro Ottawa did not call in or arrange event-specific resourcing in advance. Standard operational protocols were maintained, with regular after-hours teams on standby to handle initial emergency response, while on-call management continued to actively monitor the weather.
As outage volumes escalated, additional resourcing was brought in to support restoration efforts.
3. If the distributor did have prior warning, did the distributor issue any alert to the public warning of possible outages resulting from the pending Major Event?
No.
4. Did the distributor train its staff on the response plans to prepare for this type of Major Event?
Yes.
DURING THE MAJOR EVENT
1. Please identify the main contributing cause of the major event as per the table in section 2.1.4.2.5 of the electricity reporting and recording keeping requirements
- Loss of supply
- Lightning
- Adverse weather - Wind
- Adverse weather - Snow
- Adverse weather - Freezing rain/ice storm
- Adverse environment - Fire
- Adverse environment - Flooding
- Others
Please provide a brief description of the event. If the event was caused by weather conditions, please specify the type of weather involved – such as high winds, freezing rain, tornadoes, ice
storms, blizzards, heavy rainfall, flooding, or lightning storms.
The event consisted of highly localized severe thunderstorms with recorded wind gusts exceeding 100km/h, which led to extensive tree contacts, downed branches, and equipment breakage.
2. Was the IEEE Standard 1366 used to derive the threshold for the Major Event?
Yes, used IEEE Standard 1366
3. When did the Major Event begin?
August 12th, 2026
Time: (10:25 p.m.)
4. If the Major Event was not caused by adverse weather, did the distributor issue any information about this Major Event, such as estimated times of restoration, to the public during the Major Event?
No
If yes, please provide a brief description of the information. If no, please explain:
N/A - this major event was caused by adverse weather
5. How many customers were interrupted during the Major Event?
37,916 customers were interrupted during the Major Event.
What percentage of the distributor's total customer base did the interrupted customers represent?
9.9%
Please provide any additional comments relevant to question #5:
N/A
6. How many hours did it take to restore 90% of the customers who were interrupted?
14.30 hours
7. How many customers experienced service interruptions lasting less than 24 hours?
37,396
8. How many customers experienced service interruptions lasting between 24 and 48 hours?
435
9. How many customers experienced service interruptions lasting between 48 and 96 hours?
85
10.How many customers experienced service interruptions lasting between 96 and 168 hours?
0
11.How many customers experienced service interruptions lasting over 168 hours?
0
12. Were there any outages associated with loss of supply during the outage?
No.
If yes, please report on the duration and frequency of the loss of supply outages:
N/A
13. In responding to the Major Event, did the distributor utilize assistance through a third party mutual assistance agreement with other utilities?
Yes.
If yes, please provide the name of the utilities that provided the assistance:
Hydro One provided mutual assistance for this event.
14. Did the distributor run out of any needed equipment or materials during the Major Event?
No.
If so, please describe the shortages:
N/A
15.Provide the following characteristics of the Major Event:
i. Total number of feeders interrupted during the course of the event
29
ii. The maximum number of customers that were concurrently without power at any point during the event.
20,483
16. What is the total number of damage assessments performed by the distributor during the course of the event?
27
17.What percentage of damage assessments were completed:
i. Within 4 hours after the interruption began
19%
ii. Within 8 hours after the interruption began
33%
iii. Within 12 hours after the interruption began
74%
iv. Over 12 hours after the interruption began
26%
18. What communication methods were used to inform customers during the Major Event? Select all that apply:
- Distributor's website
- Social media
- Text message
- Telephone line
- Radio broadcast
- Others
If Other was selected please specify
Outage map banner, News release (PSA), media interview given
19. During the Major Event, did any of the communication methods used become unavailable? If so, identify which one(s).
N/A
20. Provide SAIDI and SAIFI values for this Major Event.
SAIDI: 0.357
SAIFI: 0.099
AFTER THE MAJOR EVENT
1. What actions, if any, are being taken to be prepared for or mitigate such major events in the future (i.e. staff training, process improvements, system upgrades)?
- No further action is required at this time
- Additional staff training
- Process improvements
- System upgrades
- Others
Additional Comments:
Hydro Ottawa’s Business Continuity and Emergency Planning program employs an all-hazards approach to ensure operational readiness during disruptions. Through ongoing post-event evaluations, we continuously refine our emergency response plans and operational processes to enhance future event preparedness and mitigation.