Piedra Libre - Alerta granizo

Know before the hail strikes.

Piedra Libre monitors your home, workplace, or farm and alerts you when hail is approaching, giving you time to park your car, cover your garden, or bring your plants indoors.

Piedra Libre is an independent app: it is not owned, affiliated with, or represented by the National Meteorological Service (SMN) or any other public agency. The official alerts we display are from the SMN and can be accessed at their source: https://www.smn.gob.ar/alertas

HOW IT KNOWS HAIL IS COMING
It cross-references four sources for each location you save:
• Official alerts from the National Meteorological Service.

• Lightning data from the GOES-19 satellite, every 20 seconds: when a storm begins to produce multiple lightning strikes, hail is usually imminent.

• Cloud height, also from satellite data: rapidly developing storms are the ones that produce hail.

• Hourly forecasts from three international models. We calibrated it with nearly one hundred real hailstorms in Argentina.

WHEN WILL THE STORM ARRIVE?
If a storm is heading your way, the app tells you approximately when it will arrive, based on how its lightning has moved in the last half hour.

LIVE RADAR AND SATELLITE
See where lightning is happening now, how high the clouds are, and what's happening at any point on the map.

NEIGHBORS
Reports from people who see hail, including size, photo, and comment. Neighbors in the area confirm if they are real.

FREE
Alerts for one location, radar, forecast, and reports.

PREMIUM
• Alerts for up to 10 locations.

• The time window in which the storm will arrive, its direction, and speed.

• Notification the night before if there is a risk of storms tomorrow.

• Customizable quiet hours.

• What each forecast model says.

• No ads. Monthly, annual, or season pass valid until March 31.

SOURCES
• Official alerts and warnings: National Meteorological Service (SMN) – https://www.smn.gob.ar/alertas
• Lightning and cloud height: NOAA GOES-19 satellite – https://www.goes.noaa.gov
• Forecast: GFS, ECMWF, and ICON models via Open-Meteo – https://open-meteo.com
• Radar: RainViewer – https://www.rainviewer.com

Piedra Libre is our own estimate and does not replace official warnings: if the SMN issues an alert, follow their instructions. We do not ask for your name, email, or phone number.