prevented its waters from becoming stratified and it has been inferred that Lake Estancia featured bottom currents. Silty water might have reached large distances from the shoreline, depositing its silt far into Lake Estancia. The gypsum in the lake deposits may have formed on the shoreline and was transported into Lake Estancia by winds. Overflow A broad saddle at elevation separates the Estancia basin from the Pinos Wells basin to the south. Initial research did not encounter shoreline landforms at the elevation of this sill and thus concluded that no overflow took place, but in the mid-20th century traces of a former shoreline were found above the sill elevation. Further late-20th century research did not find evidence of shorelines at overflow elevation or of flow at the supposed sill. The lake probably did not overflow during the Wisconsin glaciation; if there was overflow it took place over 130,000 years ago. If Lake Estancia overflowed under maximum highstands, it would have spilled into the Pinos Wells and Encino Basins southeast of the Estancia Valley, forming a lake with the maximum elevation of in the two basins. The maximum height would have been set either at the northern margin of the Encino Basin by a sill to the Pintado Canyon or by a saddle east of Encino, New Mexico at Vaughn, New Mexico. In the first case, the overflow would have reached the Pecos River via Pintada Creek; in the second case it would have eventually disappeared underground into karstic terrain. Together, the Pinos Wells, Encino and Estancia lakes would have covered an area of . During the Wisconsin glaciation when Lake Estancia did not overflow, each of these basins might have been occupied by separate closed lakes although evidence for the existence of such a lake in the Pinos Wells basin is scant. The sill limiting Lake Estancia's height was probably downcut if it ever carried water. Climate Today, the mean temperature of the valley is about . Precipitation is less than and much less than the annual evaporation rate of . Thus, permanent lakes cannot exist in the Estancia Valley under present-day conditions. The climate is characterized by Pacific cyclones during winter and the North American Monsoon during summer, which deliver moisture coming from the Gulf of California, Gulf of Mexico and the Pacific Ocean. Precipitation occurs in comparable quantities both in summer and winter but, given the high summer