City vs city
Johnston vs Rock Hill, SC
Rock Hill currently scores 2 points higher overall than Johnston, with the largest gap in hail.
Use this comparison for relocation decisions, insurance shopping, and hazard-prioritized mitigation planning.
Hazard breakdown
Scores describe each city’s reference grid tile, not every property. A missing model is unavailable, not zero risk. Air quality uses an ingested EPA AirNow snapshot and may not reflect current conditions; other factors describe baseline exposure. The overall score blends different hazards and is not a probability of damage. Read the scoring methodology and sources.
Overall
Johnston: 40/100 · Rock Hill: 42/100
Rock Hill is 2 points higher.
Flood
Johnston: 25/100 · Rock Hill: 33/100
Rock Hill is 8 points higher.
Johnston: FEMA NFHL flood zones: 3 features intersect this tile.
Rock Hill: FEMA NFHL flood zones: 13 features intersect this tile.
Wind
Johnston: 20/100 · Rock Hill: 19/100
Johnston is 1 points higher.
Johnston: Wind exposure derived from ingested design wind / climatology tiles.
Rock Hill: Wind exposure derived from ingested design wind / climatology tiles.
Lightning
Johnston: 62/100 · Rock Hill: 46/100
Johnston is 16 points higher.
Johnston: Lightning exposure derived from ingested climatology tiles.
Rock Hill: Lightning exposure derived from ingested climatology tiles.
Tornado
Johnston: 46/100 · Rock Hill: 19/100
Johnston is 27 points higher.
Johnston: Tornado risk derived from NOAA SPC historical reports.
Rock Hill: Tornado risk derived from NOAA SPC historical reports.
Hail
Johnston: 35/100 · Rock Hill: 100/100
Rock Hill is 65 points higher.
Johnston: Hail risk derived from NOAA SPC historical reports.
Rock Hill: Hail risk derived from NOAA SPC historical reports.
Storm surge
Johnston: Unavailable · Rock Hill: Unavailable
A score difference cannot be calculated without both sources.
Johnston: Storm surge model is not available for this location yet.
Rock Hill: Storm surge model is not available for this location yet.
Wildfire
Johnston: 69/100 · Rock Hill: 52/100
Johnston is 17 points higher.
Johnston: Wildfire exposure derived from ingested fire potential tiles.
Rock Hill: Wildfire exposure derived from ingested fire potential tiles.
Ingested air quality
Johnston: 26/100 · Rock Hill: 24/100
Johnston is 2 points higher.
Johnston: Air quality score derived from the latest ingested EPA AirNow AQI grid; may not reflect current conditions. See methodology for the recorded ingest date.
Rock Hill: Air quality score derived from the latest ingested EPA AirNow AQI grid; may not reflect current conditions. See methodology for the recorded ingest date.