Rain storms may be summoned from forest or ocean provinces. Once a location has produced a rain storm, another rain storm may not be summoned from that place until the first storm has dissipated. The storm will have a strength of twice the amount of piety invested in its summoning.
Storms lose one point of strength at the end of each month.
When a storm's strength reaches zero, it dissipates. While the storm exists, the summoner will get a location report for the storm's province.