Diablo
Skagit River·
Whatcom, Washington·
Built 1929·
Concrete·
389 ft tall
Physical Details
| Dam Height | 389 ft (taller than 95.7% in WA) |
| Dam Length | 1,180 ft |
| Dam Type | Concrete |
| Max Storage | 89.2K acre-ft |
| Normal Storage | 50.0K acre-ft |
| Surface Area | 770 acres |
| Drainage Area | 1,160 sq mi |
| Max Discharge | 105,300 cfs |
| Year Completed | 1929 (97 years old) |
| NID ID | WA00170 |
Safety Information
High Hazard
Loss of human life is likely if the dam fails
Emergency Action Plan: Yes
Last Inspection: August 16, 2022
State Regulated: No
Ownership
City of Seattle
Local Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Diablo?
Diablo is classified as High Hazard. Loss of human life is likely if the dam fails.
Who owns Diablo?
Diablo is owned by City of Seattle (Local Government).
When was Diablo last inspected?
Diablo was last inspected on August 16, 2022.
When was Diablo built?
Diablo was completed in 1929, making it 97 years old.
Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.