> ## Documentation Index
> Fetch the complete documentation index at: https://api-docs.iklim.co/llms.txt
> Use this file to discover all available pages before exploring further.
# Thunderstorm Notification
> Polygon-based thunderstorm lifecycle payload with severity, timing, and lightning cell analytics.
Describes the full thunderstorm window (start, end, severity) so you can orchestrate escalations minutes in advance.
Includes the exact exterior ring that intersects your registration, enabling map overlays out of the box.
Cell metrics expose flash rates, direction, and motion derived from real-time lightning telemetry.
```json theme={null}
{
"thunderstormId": "692d5b2cf4142f722546d77a",
"eventId": "EAF202512010907001",
"registrationId": "e71fedf8-a0a9-462e-a972-47dc8a5586df",
"recipientId": "recipient-04c2b9c7ad01",
"eventStartUtc": 1764580080,
"eventEndUtc": 1764582780,
"severity": "LOW",
"threshold": 3,
"speedKmh": 38.892,
"distance": 0,
"affectedPolygon": {
"exterior": [
{ "lng": 28.943784, "lat": 40.979168 },
{ "lng": 28.943784, "lat": 41.051032 },
{ "lng": 29.015216, "lat": 41.051032 },
{ "lng": 29.015216, "lat": 40.979168 },
{ "lng": 28.943784, "lat": 40.979168 }
],
"holes": []
},
"cell": {
"area": 8.999704133858742,
"speedKmh": 33.293898860271185,
"direction": 255,
"distance": null,
"centroid": {
"lng": 28.9795,
"lat": 41.0151
},
"polygon": {
"exterior": [
{ "lng": 28.961642, "lat": 41.0151 },
{ "lng": 28.970571, "lat": 41.033066 },
{ "lng": 28.988429, "lat": 41.033066 },
{ "lng": 28.997358, "lat": 41.0151 },
{ "lng": 28.988429, "lat": 40.997134 },
{ "lng": 28.970571, "lat": 40.997134 },
{ "lng": 28.961642, "lat": 41.0151 }
],
"holes": []
},
"flashRates": {
"inCloud": 4.33,
"cloudToGround": 0.34,
"total": 4.67
}
}
}
```
| Field | Type | Description |
| ---------------- | ------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `thunderstormId` | string | Unique ID for this thunderstorm instance; use it to correlate updates. |
| `eventId` | string | Business-friendly identifier that aligns with the iklim.co event catalog. |
| `registrationId` | string | Subscription/registration that subscribed to the thunderstorm product. |
| `recipientId` | string | Caller-defined identifier that maps the notification back to your customer/asset record (feel free to use hashed/anonymized unique IDs instead of human labels for GDPR compliance); keep it unique per geometry because only one registration is allowed for the same area per `recipientId`, and use it when you prefer to locate your target without storing our `registrationId`. |
| `eventStartUtc` | number | UTC epoch seconds for when the storm will enter the protected area. |
| `eventEndUtc` | number | UTC epoch seconds for when the storm is expected to leave the area. |
| `severity` | enum | Discrete bucket such as `LOW`, `MEDIUM`, or `HIGH` based on flash density and speed. |
| `threshold` | number | Minimum lightning flash count per minute that qualifies the cluster as a thunderstorm. |
| `speedKmh` | number | Forecasted forward speed of the whole thunderstorm envelope in km/h—pair it with `direction` to project the track. |
| `direction` | number | Bearing in degrees (0° = North, clockwise) that shows where the envelope described by `speedKmh` is heading. |
| `distance` | number | Meters between the storm edge and your registration centroid (`0` when currently overhead). |
#### `ThunderstormSeverity` catalog
| Value | Meaning |
| -------- | ----------------------------------------------------------------------------------------------------- |
| `LOW` | Sporadic flashes with limited coverage; treat as FYI or low-touch workflows. |
| `MEDIUM` | Sustained lightning clusters capable of causing localized damage; escalate to mid-tier playbooks. |
| `HIGH` | Widespread, fast-moving cells with extreme flash rates; trigger your highest alert level immediately. |
#### `affectedPolygon`
| Field | Type | Description |
| ---------------------------- | --------------- | ---------------------------------------------------------------------------------------- |
| `affectedPolygon.exterior[]` | `array` | Clockwise list of longitude/latitude vertices that intersect your registration boundary. |
| `affectedPolygon.holes[]` | `array` | Optional voids to subtract (usually empty). |
#### `cell`
| Field | Type | Description |
| ------------------------------- | --------------- | -------------------------------------------------------------------------------------------------------------------------------- |
| `cell.area` | number | Cell area in square kilometers. |
| `cell.speedKmh` | number | Speed of the most active lightning cell (km/h); use with `cell.direction` to see how quickly the core is approaching or leaving. |
| `cell.direction` | number | Movement bearing in degrees (0° = North, clockwise) aligned with `cell.speedKmh`, highlighting the lightning core's heading. |
| `cell.distance` | number/null | Kilometers from the cell centroid to the registered asset; `null` when it overlaps. |
| `cell.centroid.lng` | number | Longitude of the lightning cell centroid. |
| `cell.centroid.lat` | number | Latitude of the lightning cell centroid. |
| `cell.polygon.exterior[]` | `array` | High-resolution outline of the most energetic cell. |
| `cell.polygon.holes[]` | `array` | Optional interior voids for the cell polygon. |
| `cell.flashRates.inCloud` | number | In-cloud flashes per minute. |
| `cell.flashRates.cloudToGround` | number | Cloud-to-ground flashes per minute. |
| `cell.flashRates.total` | number | Sum of all flash types per minute. |
Convert `eventStartUtc`/`eventEndUtc` to your user's timezone and show a friendly countdown in customer apps.
Overlay `affectedPolygon` + `cell.polygon` on your GIS layer to highlight precisely where the danger lies.
When `severity` ≥ `MEDIUM` and `distance` ≤ 5 km, automatically notify high-value customers or halt risky operations.