Query Hail History at a Point (GeoJSON)

Query historical hail activity at a single lat/lon point, returned as a GeoJSON FeatureCollection.

Each hail event is analyzed by FLASH AI using radar data and nearby ground reports to produce calibrated size estimates. Archive covers 2021-05-01 to present.

Required Parameters

• lat: Latitude (20°–55° N, CONUS archive coverage)
• lon: Longitude (−130°–−60° W)
• start: ISO-8601 datetime, earliest supported: 2021-05-01T00:00:00
• end: ISO-8601 datetime

Optional Parameters

• size: Minimum hail size in inches to include (default 0.0)

Response, GeoJSON FeatureCollection

Two feature types are returned:

primary_location feature

Properties:

• max_hail_size_in: peak FLASH AI hail size estimate across all events
• events[]: list of distinct storm events, each with:
  • timestamp / start_time / end_time / duration_min
  • estimated_hail_size_in: FLASH AI hail size estimate
  • raw_mrms_hail_size_in: radar-derived size before FLASH AI calibration
  • coverage: spatial coverage fraction 0–1 within the surrounding area
  • coverage_label: low / medium / widespread
  • confidence: integer 1–5 (for sorting)
  • confidence_label: marginal / low / moderate / high / exceptional
  • hail_index: 0.0–5.0 impact index (≥4.0 = dispatch, 3.0–3.9 = evaluate)
  • nearest_spc_report_id: ID of nearest ground report used in the estimate, or null
  • detection_source: mrms (radar-detected) or spc_confirmed (radar recorded nothing here, but a nearby human ground report confirms hail; shown with raw_mrms_hail_size_in=0.0, confidence capped at high)
  • spc_distance_km: only present when detection_source=spc_confirmed

spc_report features (0 or more)

Nearby ground reports used in the FLASH AI estimate, with size_in, datetime, location, and distance_mi from the query point.

Archive Coverage

2021-05-01 to present (5-year rolling window).

curl -X GET "https://example.com/lookback/hail/?end=2023-05-15T23%3A59%3A59&lat=35.4676&lon=-97.5164&size=0&start=2023-05-15T00%3A00%3A00"

{  "type": "FeatureCollection",  "features": [    {      "type": "Feature",      "geometry": {        "type": "Point",        "coordinates": [          -97.5164,          35.4676        ]      },      "properties": {        "id": "loc-a1b2c3d4",        "type": "primary_location",        "start_time": "2023-05-15T00:00:00+00:00",        "end_time": "2023-05-15T23:59:59+00:00",        "max_hail_size_in": 1.75,        "events": [          {            "timestamp": "2023-05-15T18:00:00+00:00",            "start_time": "2023-05-15T18:00:00+00:00",            "end_time": "2023-05-15T18:48:00+00:00",            "duration_min": 48,            "estimated_hail_size_in": 1.75,            "raw_mrms_hail_size_in": 1.65,            "coverage": 0.22,            "coverage_label": "medium",            "confidence": 4,            "confidence_label": "high",            "hail_index": 4.1,            "nearest_spc_report_id": "spc-hail-20230515-1810-3546n09751w",            "detection_source": "mrms"          }        ]      }    },    {      "type": "Feature",      "geometry": {        "type": "Point",        "coordinates": [          -97.51,          35.46        ]      },      "properties": {        "id": "spc-hail-20230515-1810-3546n09751w",        "type": "spc_report",        "size_in": 1.75,        "datetime": "2023-05-15T18:10:00+00:00",        "location": "3 SSW Oklahoma City",        "distance_mi": 1.4      }    }  ]}