It is also possible that the inflow into an open lake could decrease so much that any outflow would dry the lake up completely — that is, the open lake would become a closed lake. The only lake that is currently an open lake for which there is any evidence of a closed lake existing in the same location in the past is Lake Malawi in Africa. It is known that in very dry periods, outflow from the Shire River — Lake Malawi's only outlet — can drop precipitously, and it is strongly believed that during past dry periods outflow from Lake Malawi has ceased entirely and salt has accumulated in the lake, especially during the Last Glacial Maximum and other similarly dry periods.