The following paper explain a new methodology for an early warning system for rain events at a campsite over the Pyrenees in Lleida in the Northeast of Spain. The typology of rainfall events is well known in this part of the Pyrenees. They are normally events with high intensity and short duration and are mainly distributed over summer and springtime. This temporal distribution of the rainfall becomes the main treat in this part of the country, due to during this period of the year there is a great amount of tourist mobility that search for natural environments. Most of the campsites of the zone are located next to the rivers; therefore, many of them are subjected to a high probability to suffer damages under heavy rain events and the consequent floods. Due to that and considering that the campsites might be full of people during this time, it is highly recommended to have and early warning system in the case the campsites may be flooded by a heavy rain event.