SkyGround

County-level natural hazard risk data for researchers

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Grainger County, TN

Population: 23,527 · FIPS code: 47057

Very Low Overall risk index: 18.6 / 100 (percentile among US counties)

Hazard breakdown

Hazard NRI rating NRI score NOAA events
(2016–2025)
Wildfire Very Low 48.7 0
Inland Flooding Very Low 33.6 4
Coastal Flooding Not Applicable — 0
Earthquake Relatively Low 67.6 —
Heat Wave Very Low 14.3 0
Tornado Relatively Low 39.2 1

NOAA event counts are recorded county-level storm events from the NOAA Storm Events Database for 2016–2025. NOAA does not track earthquakes, and some hazard reports are filed by NWS forecast zone rather than county, so these counts are a partial, not exhaustive, record of recent activity. See the methodology page for details.

Federal disaster declaration history

Grainger County has been included in 20 federal disaster declarations between 1973 and 2026, most recently for Winter Storm in 2026 (SEVERE WINTER STORM).

Source: FEMA OpenFEMA Disaster Declarations Summaries. Counts reflect county-level declaration records (a single disaster can produce more than one record per county), not modeled risk.

Geomagnetic latitude

Grainger County sits at approximately 45.4°N geomagnetic latitude. Aurora is rarely visible this far from the geomagnetic poles, even during the most severe (G5) geomagnetic storms — though historic extreme storms have occasionally been seen at unusually low latitudes. See current space weather conditions for live geomagnetic activity and aurora forecasts.

Geomagnetic latitude is an approximate dipole-model calculation based on this county's geographic centroid (US Census Bureau). See the methodology page for details and limitations.

What these ratings mean

Each score reflects how Grainger County's expected losses from that hazard compare to every other county in the country, based on FEMA's National Risk Index. A "Very High" rating means this county is among the most exposed in the US for that hazard relative to other counties — it does not mean a disaster is likely this year. See the methodology page for how these scores are calculated.