Vernal pools are seasonal wetlands that occur in a depression, which is covered by shallow water for some amount of time through the winter and spring, and may be completely dry in the summer and fall. Vernal pools can be a range of sizes, from small puddles to large ponds. Melting snow produces these pools in the late winter and spring, during which wildflowers often take over right up to the edge of the pool. By the onset of summer, the pools will be gone due to evaporation.