The ANELFA field activities take place each year from April to October.
The area covered by the ANELFA is distributed over four regions and represents a total of 55,000 km².
- About 650 manually activated ground generators are ready to be switched on by volunteers (essentially farmers and wine growers).
- The hail risk forecast is done by Keraunos according to a special agreement.
- The warning must be given 4 hours in advance by the meteorological services, and then transmitted to the emitting stations in the concerned area through a computerized telephone system. The generators emit their smoke from the burning of an acetone silver iodide solution and the ice forming particles scatter in the storm development areas. The production of ice-forming nuclei active at -15°C is of 2x1011.s-1 per generator. Emissions last until the end of the hail risk period, a warning having an average duration of about 10 hours.