Reading the storm
Loading the page…Reading the storm
Loading the page…Privacy
Effective and last updated
StormCrownHD is not an official warning service. Alerts shown here come from the National Weather Service, but delivery can be delayed. Follow instructions from the NWS and local emergency officials, keep Wireless Emergency Alerts or a NOAA Weather Radio on, and call 911 in an emergency.
Sign-in is handled by Clerk. When you create an account, Clerk stores your email address, your name if you provide one, and your sign-in details. We keep a matching StormCrownHD record with your Clerk user ID, email, display name, preferred units and home place.
Like any website, our hosting provider receives your IP address and browser details with each request, and so do the map and imagery services your browser loads maps from (see Location). We use IP addresses briefly to rate-limit heavy features such as search and The Guide. We use Vercel Web Analytics to count page views in aggregate; it does not use cookies or build a profile of you.
StormCrownHD never tracks your location in the background. We only use a location when you search for one, save a place or route, open a briefing for a place, or tap a “use my location” control and grant your browser's permission. To fetch weather for a location, our servers send its coordinates (not your identity) to the National Weather Service and the other data sources listed on our About page; place searches go to Photon (komoot) or the U.S. Census Bureau geocoder, and route requests go to the OSRM routing server, or to the Valhalla routing server if OSRM is unavailable (both run by FOSSGIS).
Maps work differently. When you view a map, your browser loads the base map directly from OpenFreeMap, and radar and satellite imagery directly from NOAA (NCEP and nowCOAST), NASA GIBS and the Iowa Environmental Mesonet. As with any web request, these services receive your IP address and which part of the map you are viewing, so a map centered on your location reveals that area to them. We send them no account information.
The Guide and The Briefing are written by Claude, an AI model from Anthropic. When you ask The Guide a question, we send Anthropic your question, the earlier messages in that conversation (including the weather data and place details looked up for earlier answers), the location or alert you asked about, and the official weather data needed to answer.
If you are signed in and refer to one of your saved places (for example “home” or “my mom's house”), The Guide looks up your saved places to find the one you mean, so Anthropic may receive your list of saved places (up to 25): each place's name, type and coordinates, any address you entered, and any event dates and times. Notes you add to a place are not sent. These details are kept with that conversation, and may be sent again with later questions in it, until you delete the conversation.
Briefings are generated from public National Weather Service data for a location and contain no personal information.
Anthropic processes this data to provide the service under its commercial terms; see Anthropic's privacy policy. Please do not share sensitive personal information in your questions.
We rely on a small number of service providers, each only for the job described:
Map and imagery services (OpenFreeMap, NOAA, NASA GIBS and the Iowa Environmental Mesonet) are independent public services rather than our providers: your browser contacts them directly, as described under Location, and we share nothing about you with them.
We may disclose information if the law requires it, or to protect the safety of people or the service. If StormCrownHD were ever transferred to a new owner, this policy would continue to apply to your data.
Clerk sets the cookies needed to keep you signed in. StormCrownHD itself keeps a few things in your browser's local storage so they work without an account: your Ready checklist progress, and the area or location you last chose in The Watch. They stay on your device until you clear them; signing out removes checklist progress that belongs to your account. We do not use advertising or cross-site tracking cookies.
Depending on where you live, you may have additional rights to access, correct or delete your information. We honor those requests for everyone, wherever you live.
All traffic is encrypted with HTTPS. Your saved data is only read and written by our servers, and every request is checked against your signed-in account so no one else can see what you save. No system is perfectly secure, so we keep only what the service needs.
StormCrownHD is not directed to children under 13, and we do not knowingly collect their personal information. If you believe a child has created an account, contact us and we will delete it.
If we change this policy, we will update the date at the top and, for significant changes, tell signed-in users in the app. Questions or requests: privacy@stormcrownhd.com. See also our Terms of use.