Flood Zone Comparison
Compare key metrics between 57221 57221, SD — Zone AE and 77304 77304, TX — Zone AE. Data sourced from FEMA National Flood Hazard Layer (2025).
| Metric | 57221 57221, SD — Zone AE | 77304 77304, TX — Zone AE |
|---|---|---|
| name | 57221 57221, SD — Zone AE | 77304 77304, TX — Zone AE |
| zip code | 57221 | 77304 |
| city | 57221 | 77304 |
| state | South Dakota | Texas |
| state code | SD | TX |
| category | High Risk | High Risk |
| flood zone | Zone AE (High Risk — 100-Year Floodplain) | Zone AE (High Risk — 100-Year Floodplain) |
| risk level | High Risk | High Risk |
| annual flood prob | 1% annual chance (100-year flood) | 1% annual chance (100-year flood) |
| insurance required | Required for federally-backed mortgages | Required for federally-backed mortgages |
| avg annual premium | 3,333 | 3,332 |
| base flood elevation | 25 ft | 10 ft |
| historical floods | 9 recorded flood events in the past 50 years. Most recent major flood: 2008 | 10 recorded flood events in the past 50 years. Most recent major flood: 2012 |
| nearest water | local river (4.1 miles) | Lake Ontario (2.0 miles) |
| elevation ft | 939 | 635 |
| population | 73,446 | 63,899 |
| median home value | 550,618 | 409,523 |
| flood damage risk | 40-60% chance of flood damage over a 30-year mortgage. Estimated average damage per flood event: $73,004 | 40-60% chance of flood damage over a 30-year mortgage. Estimated average damage per flood event: $131,906 |
| mitigation tips | Elevate utilities above base flood elevation; install sump pumps with battery backup; consider flood-proofing ground floor; maintain flood insurance; create an emergency evacuation plan; store important documents above flood level. | Elevate utilities above base flood elevation; install sump pumps with battery backup; consider flood-proofing ground floor; maintain flood insurance; create an emergency evacuation plan; store important documents above flood level. |
| fema map id | 3161C453J | 2446C440J |
| last updated | 2025-01-01 | 2025-01-01 |
Our team analyzes data from FEMA National Flood Hazard Layer to deliver accurate, up-to-date information. All data is verified and cross-referenced with official sources.