Snow falling on warm ground can melt, usually slowly, which allows time to moisten the ground / dirt and perhaps percolate into the water table, which is a good way to help ease a hydrological drop. On the flip side, snow can often sublimate from a solid directly into gaseous water vapor before it melts enough to have any impact on the ground moisture. In a drought, the best case scenario is is a rapid melt so that the moisture can at least form runoff for accumulation in a lake behind a conservation dam.

One additional benefit for agricultural concerns is that snow is typically much higher in nitrogen than rain, and is often highly beneficial as a natural supplemental fertilizer or soil enrichment, espcially in spring as the growing season is getting underway.