When disaster draws near, Soterra makes it clear.

A disaster hotline you can call from any phone, no sign-up, along with a mobile companion app that shows the same verified alerts live. Soterra watches official sites and social media, keeps only what it can trust, and notifies you immediately when something changes.

Call Soterra See the demo

In danger? Hang up and dial 911. Soterra shares information and can’t send help.

0:00to 2:30 Scroll to run the clock

Live now. The line runs the Marina Earthquake demo below.

Built at Cal Hacks 13 with

Knowing sooner is what gets people out in time.

On the night of July 4, 2025, a flood tore through Kerr County, Texas. More than 100 people died, many of them children. The federal alert system, the one built to wake people up, went unused.

ProPublica found at least 15 federally declared disasters since 2016 where the alerts came late, or never came.

Source: ProPublica, reported by Environmental Health News, 29 August 2025.

When the alert doesn’t come, people turn to social media, because that’s where news breaks first. Agencies post there before their websites update, and sometimes the websites go down.

But that’s also where the rumors live. Soterra uses both, and keeps only what it can trust.

The minute that matters.

Scroll to run the clock on the demo we built for Cal Hacks: an earthquake at the Palace of Fine Arts, one caller, one callback.

Simulated scenario. The quake, the agencies and every post are demo data.

  1. 2:03 PM

    The ground shakes. No alert comes.

    A magnitude 6.4 earthquake hits the Palace of Fine Arts during Cal Hacks judging. You’re studying at the Marina Branch Library, a few blocks away. Your phone stays quiet.

    Sunday, October 25

    2:03

    No notifications

  2. 2:03 PM

    News breaks on social media first.

    Within seconds the posts pour in. Some are true. Some are about a crushed robot dog and a man in an Iron Man suit. None of them is confirmed.

    2:03

    #sfquake Latest

    • Ava @async_ava · now

      smell of gas on Baker St near the Palace, firefighters telling everyone to move back

      Unverified

    • Hannah @hackerhannah · 2s

      #PalaceOfFineArts is in ruins. the colonnade on the lagoon side is down

      Unverified

    • Diego @dev_diego · 3s

      I swear I saw Iron Man carry someone out of the east hall. or a guy in a really good cosplay

      Unverified

    • Jordan @jordan_ships · 5s

      my robot dog got crushed by a falling column. RIP Sparky

      Unverified

  3. 2:03 PM

    You call. Soterra doesn’t guess.

    Nothing trustworthy is out yet, so Soterra says so instead of guessing. It saves your question, and you ask for a callback.

    2:03

    Soterra

    0:15

    • This is Soterra, the disaster info line. In danger? Hang up and dial 911. How can I help?
    • I’m in San Francisco. What just happened?
    • I don’t know that one yet, but I’ve saved your question.
    • Call me back when you know what happened.
    • Okay, I’ll call you when there’s news about San Francisco.

  4. 2:03 PM

    Meanwhile, it keeps only what it can trace to a trusted source.

    Precise queries go out across 13 official sites, agency accounts and social media. Soterra keeps just what it can trace back to a trusted source, and the moment something real comes in, like an update from SF Fire, it knows who’s waiting to hear it.

    2:03

    Inside Soterra

    13 official sites and the #sfquake feed

    • AlertSF (Demo) · page

      Evacuation Order for the Marina District

      Official

    • SF Fire Department (Demo) · @sffd_demo

      All Cal Hacks attendees and staff are accounted for.

    • Hannah · @hackerhannah

      #PalaceOfFineArts is in ruins

      Signal, not spoken

    • Diego · @dev_diego

      I swear I saw Iron Man…

      Signal, not spoken
    • Trusted source
    • Sources agree
    • Cited

  5. 2:04 PM

    A minute later, your phone rings.

    The Marina is under an evacuation order, and you’re in the zone. Soterra tells you the nearest shelter, who said so, and when, then takes your questions.

    2:04

    Soterra

    Calling you back · 0:40

    • Hi, this is Soterra. I’m calling about the update you asked for.
    • Update from AlertSF (Demo), 2:03 PM: Evacuation Order for the Marina District. Leave now and go to Hamilton Recreation Center, 1900 Geary Boulevard.
    • Am I in an evacuation zone?
    • The order covers the Marina District north of Lombard Street, from Van Ness Avenue to Lyon Street. AlertSF (Demo), 2:03 PM.
    • Is everyone at the Palace of Fine Arts okay?
    • All Cal Hacks attendees and staff are accounted for. SF Fire Department (Demo), 2:03 PM.

  6. 2:05 PM

    The update lands in your texts.

    By the time you’re out the door, the update is in your messages, with the time it was issued and a way to stop. Miss the call, and the text still comes.

    2:05

    Soterra

    Today 2:05 PM

    Update on San Francisco (2:05 PM PT):

    As of 2:03 PM PT: Evacuation Order for the Marina District. Leave now and go to Hamilton Recreation Center, 1900 Geary Boulevard.

    Reply STOP to stop all Soterra texts.
    In danger? Call 911.

What counts as a source.

Soterra doesn’t decide that a stranger’s post is true. It sorts everything it reads into three tiers, and only two of them can ever reach a caller.

Where it comes from Label What Soterra does with it
Agency sites and official feedsEmergency management, fire, weather, roads, transit Official Answers come from these, always with the source name and the time.
Agency accounts on social mediaAn allowlist of official accounts Used as sources and labeled as such. They keep working when an agency’s website is slow or down.
Everyone elsePublic posts, eyewitnesses, rumors Unverified signal Never spoken and never used as an answer. A claim reaches a caller only after an official source says the same thing.
“Also reported by SF Emergency Management.”
Added when an independent agency says the same thing.
“Sources differ on the figures.”
Said when agencies disagree, instead of picking one.
“I don’t know that one yet, but I’ve saved your question.”
Said when nothing official exists. The question is answered later, by call or text.

How it’s built.

Cartesia runs the call, and Convex stores everything and places the callbacks. Apify pulls in pages and posts, and Claude keeps only the facts it can quote. Then our code double-checks before anything is said.

  1. Sources

    Official sites, agency accounts and social media.

  2. Crawls pages and posts on a schedule, and early when a burst of posts suggests news.

  3. Extracts only facts it can quote from the page, with the time the agency gave.

  4. Stores everything, runs the checks, knows who’s waiting and places the callbacks and texts.

    • Trusted source
    • Sources agree
    • Cited

  5. The phone number and the voice agent. Every turn of a call asks Convex for a grounded answer.

  6. You

    Any phone, or the companion app. A call when news changes, a text with the details.

Information flows from the sources to you. A caller’s question goes the other way: Cartesia sends each turn to Convex, which checks for danger first, then answers only from stored, cited bulletins.

  • Danger first.

    If you sound like you’re in danger, the first thing you hear is to hang up and dial 911. Soterra never claims to send help.

  • Grounded or silent.

    Every answer names its source and time. Stale information is marked as needing reconfirmation.

  • No address guessing.

    It reads you the official zone. It never says whether a specific address is inside it.

  • Private by default.

    Transcripts are kept only with permission. Say “forget me” and it deletes what it saved for your number.

Built at Cal Hacks 13 by four people.

  • LeiaThe voice agent on the phone line, and texts
  • Alonso and HikaruThe backend: call pipeline, grounding, callbacks and the iOS app
  • DhweyaIngestion: official feeds, Apify crawls and social media

When every minute counts, no one should have to search, scroll, wait, or guess.

Soterra gives people trusted information the moment they need it, in words anyone can understand.

Call Soterra