Transparent by design

How condition ratings work

Ratings are created by deterministic TypeScript rules, not artificial intelligence. The same inputs always produce the same assessment, and each result includes its contributing factors.

Source adapters

• National Weather Service: point forecasts and active alerts. Forecasts are cached for about 45 minutes; alerts for about 10 minutes.
• USGS Water Data APIs: modern OGC API observations for configured river stations, including gage height, streamflow, timestamps, and trend where enough samples exist. Results are cached for about 15 minutes.
• National Park Service: optional alerts for Congaree National Park when a server-side API key is configured. Results are cached for about 30 minutes.

Lake Murray, Lake Wateree, Lake Marion, and Lake Moultrie currently use weather and official utility links but do not claim live USGS lake-level data. River station support is configured for the Congaree, Broad, Saluda, and Wateree rivers and Cedar Creek.

Signals and rating rules

Rules consider severe weather, flood alerts, park closures, extreme heat, wind, precipitation probability, rising water, stale observations, and missing data. Water activities receive added wind and water-level scrutiny. Severe or conflicting official signals take priority over otherwise favorable weather.

Freshness

• Updated recently: within roughly two hours.
• Updated today: more than two but no more than 24 hours old.
• Stale: older than 24 hours.
• Unavailable: no valid observation time was returned.

Missing data and resilience

External responses are validated before display. Malformed or failed responses produce a clear unavailable state instead of a broken page. The caching layer can return a previously valid response for a limited period when a source is temporarily unavailable.

Local demonstration mode

Development and automated tests use realistic fixtures by default. They include normal weather, wind, high water, stale data, a park notice, and missing observations. Demonstration data is identified in the interface and must not be mistaken for current field conditions.

Limitations

Conditions can change between observations, and a station may not represent every cove, trail, launch, or river reach. Ratings are planning aids, not safety guarantees. Verify official warnings, closures, releases, access, and regulations before departure.