Data Sources

Last updated: April 27, 2026

Grand Tracker is a passive presentation of public data. We do not generate water-level, weather, or lightning data ourselves — we display readings from official agency feeds and clearly mark each one. This page lists every external source the app uses, with a link to the authoritative original.

    Important: if you see a difference between this app and the agency's own website, the agency is authoritative. Always confirm boating, swimming, storm-shelter, and water-safety decisions against the agency source listed below.
  

Federal agencies

USGS — U.S. Geological Survey

Lake gauge readings (pool elevation, water temperature, discharge) used in the Lake tab and conditions strip. Data is in the public domain. We retrieve from the USGS Water Services API and cache it for short periods to limit upstream load.

Authoritative source: waterservices.usgs.gov · Oklahoma-Texas Water Science Center

NOAA / National Weather Service

Forecasts, current conditions, watches, and warnings used in the Wx tab. Data is in the public domain. We retrieve from the NWS public API and cache short-lived responses.

Authoritative source: api.weather.gov · weather.gov · Disclaimer: NWS disclaimer

USACE Tulsa District — U.S. Army Corps of Engineers

Pensacola Lake (Grand Lake) operations data — current pool elevation and dam-release information. Data is in the public domain.

Authoritative source: swt-wc.usace.army.mil/PENS.lakepage.html

State agencies

GRDA — Grand River Dam Authority

Lake operations news, water-quality advisories, and the public algae-advisory map. The "AI-powered GRDA bulletin" feature summarizes GRDA-published news for the user; the original GRDA post is always linked next to the summary.

Authoritative source: grda.com · Water-quality advisory map

ODWC — Oklahoma Department of Wildlife Conservation

Northeast Oklahoma fishing reports used as a fishing-conditions input on the Lake tab.

Authoritative source: wildlifedepartment.com (Grand Lake)

Real-time lightning

Blitzortung.org

Community-operated real-time lightning-strike network. Used to power the optional Lightning Alerts push feature. Data is community-contributed and provided without warranty; do not rely on it as a sole safety source. Always check NWS for severe-weather warnings.

Authoritative source: blitzortung.org

Maps

OpenStreetMap contributors / Esri

Base map tiles and imagery on the Map tab.

AI summaries

Anthropic — Claude

Powers AI-generated summaries (e.g., GRDA bulletin recap, search responses). The model can hallucinate or misinterpret source data; always verify AI-generated content against the original source linked alongside it. Do not rely on AI output for boating, weather-safety, medical, legal, or financial decisions.

Provider: anthropic.com · Privacy policy

Service providers

The following third parties power the Service but are not displayed sources of lake / weather / water-quality data:

Stripe — payment processing. Stripe privacy
OneSignal — push notification delivery. OneSignal privacy
Upstash — serverless Redis/KV used for billing state, push subscriptions, and analytics aggregates. Upstash privacy
Vercel — application hosting and edge analytics. Vercel privacy
Google Analytics 4 / Microsoft Clarity / Meta Pixel + Conversions API — anonymized usage analytics and advertising measurement, suppressed when marketing cookies are declined. See our privacy policy for details on each.

Reporting an attribution issue

If you operate one of the sources listed above and have a question about how Grand Tracker uses your data, or you want a different attribution form, contact us at howdy@grandlakeapp.com and we will respond promptly.

For the legal terms governing your use of the Service, see our Terms of Service and Privacy Policy.