// Risk Intelligence
| Risk Score | 7 / 10 High |
| Facility Type | 🌉 Bridge / Critical Crossing |
| Operator / Branch | Oregon and Washington Departments of Transportation |
| Host County | Multnomah County OR |
| Nearest City | Washington DC |
| Primary Risk Radius | 5 miles |
| Secondary Risk Radius | 20 miles |
// Strategic Significance
The Interstate Bridge crossing the Columbia River between Portland Oregon and Vancouver Washington consists of two parallel bridges built in 1917 and 1958. The older 1917 span is one of the most seismically vulnerable major bridges in the Pacific Northwest. A major Cascadia earthquake could render both bridges impassable isolating Vancouver Washington from the Portland Oregon metro area. The bridge carries I-5 which is the primary Pacific Coast highway corridor.
// Civilian Impact Assessment
Multnomah County with 800,000 residents and Clark County WA with 500,000 residents. The 1917 bridge is one of the most seismically vulnerable major bridges in the Pacific Northwest. Cascadia earthquake could isolate Vancouver WA from Portland OR. I-5 is the primary Pacific Coast corridor.
// Evacuation & Shelter Guidance
I-5, Columbia River. Multnomah County Oregon and Clark County Washington Emergency Management coordinate Cascadia earthquake and bridge closure protocols.