// Risk Intelligence
| Risk Score | 7 / 10 High |
| Facility Type | 🌊 Major Dam / Flood Control |
| Operator / Branch | US Army Corps of Engineers |
| Host County | McLean County ND |
| Nearest City | Washington DC |
| Primary Risk Radius | 100 miles |
// Strategic Significance
Garrison Dam on the Missouri River creates Lake Sakakawea — the third largest reservoir in the US by volume. The dam provides flood control for communities downstream along the Missouri River from North Dakota through South Dakota Nebraska Iowa Kansas and Missouri. The 2011 Missouri River flooding demonstrated what happens when dams must release at maximum capacity during extreme snowmelt and rainfall combinations.
// Civilian Impact Assessment
A Garrison Dam failure would send catastrophic flooding down the Missouri River affecting communities from Bismarck ND through the entire Missouri River corridor to its confluence with the Mississippi. The 2011 flooding caused billions in damage along the Missouri — a catastrophic dam failure would be orders of magnitude worse affecting millions of people across multiple states.
// Evacuation & Shelter Guidance
Bismarck and Missouri River communities downstream of Garrison Dam should monitor reservoir levels and release rates especially during major spring snowmelt events. The 2011 flooding provided valuable experience for downstream emergency planning. Monitor North Dakota DES and Army Corps of Engineers Missouri River flood forecasting. Know your floodplain elevation relative to river stage.
// Recommended Preparedness Gear
Essential preparedness items for residents within the 100-mile risk zone of Garrison Dam ND.
72-Hour Emergency Food Kit View on Amazon → Water Filtration System View on Amazon → Portable Generator View on Amazon →* ThreatMap USA participates in the Amazon Associates Program.