Lake Turkana

Long ago, volcanoes poured out lava here. Lava rocks cover much of the land.

The lake has no river flowing out of it.

ILEC explains that volcanoes were very active while the Rift Valley formed, and lava covers much of the valley floor in Kenya. A younger lava flow forms a barrier at the southern end of the lake.

The Omo River flows in from the north and brings more than 90 percent of the lake's water. Other rivers flow only after rare rains. No river flows out, so the lake loses its water mainly when it evaporates in the heat.

Volcanic activity was frequent during the creation of the Rift Valley, and Quaternary and Tertiary lavas, mainly alkaline, cover much of its floor in Kenya, with important effects on the chemistry of its lakes. Tertiary volcanic rocks lie in the south and along most of the western side; a Pleistocene lava flow forms a barrier at the southern end; Quaternary sediments dominate the west and north (ILEC).

The Omo contributes more than 90% of the inflow; other rivers are temporary. With no outlet, the lake loses water mainly by evaporation (about 2,335 mm a year), so its level is sensitive to climate and changes with the seasons and over the long term.

The lake is very salty. People call it the Jade Sea because of its color.

It is hot and windy here, and it rarely rains.

UNESCO says Lake Turkana is the largest desert lake in the world and the most salty lake in East Africa. It is often called the Jade Sea because of its beautiful color.

ILEC says most of the land around the lake gets less than 250 millimeters of rain a year, and the rain is hard to predict. At Lodwar, temperatures range from 19.5 to 39.9 degrees Celsius, and strong winds often blow from the southeast.

UNESCO: the most saline lake in East Africa and the largest desert lake in the world, surrounded by an arid landscape that is often devoid of life, and fondly called the Jade Sea for its color.

ILEC: mean annual rainfall under 250 mm in most of the surroundings, erratic and unpredictable, most likely during the 'long rains' of March to May; air temperatures at Lodwar range from 19.5 to 39.9 degrees C (mean daily 29.26 degrees C); frequent strong winds, mainly from the southeast.

Crocodiles and hippos raise their young on the lake's islands.

Many birds stop here on long journeys.

UNESCO says the islands in Lake Turkana National Parks are where Nile crocodiles, hippos and several kinds of snakes breed. It calls the area the largest Nile crocodile breeding ground in the world.

More than 350 kinds of water and land birds have been recorded, and the lake is an important stopover for migrating birds. In the muddy bays of South Island, underwater beds of pondweed shelter fish when they lay their eggs.

The island parks are breeding habitats of the Nile crocodile, the hippopotamus and several snake species, with the world's largest Nile crocodile breeding ground; the parks protect threatened reticulated giraffe, lions and Grevy's zebras, and over 350 bird species are recorded (UNESCO).

The lake is an important flyway and stopover for Palearctic migrant birds, and South Island Park is a BirdLife International Important Bird Area. Submerged beds of Potamogeton pectinatus in South Island's muddy bays shelter spawning fish.

Scientists have found very old bones near the lake. They help us learn about early humans.

There are also forests of trees that turned to stone.

UNESCO says scientists began finding fossils at Koobi Fora, north of Allia Bay, in 1969. Fossils of five kinds of early humans and human relatives have been found there, including Homo habilis, which lived about two million years ago.

There are also petrified forests: trees turned to stone, from a time when the land was moist grassland and forest instead of hot desert.

Extensive paleontological finds at Koobi Fora, north of Allia Bay, began in 1969 with Paranthropus boisei; remains of five species (Australopithecus anamensis, Homo habilis/rudolfensis, Paranthropus boisei, Homo erectus, Homo sapiens) come from one locality. UNESCO says the deposits have contributed more to understanding human ancestry and paleo-environment than any other site in the world.

Petrified forests and about one hundred archaeological and paleontological sites record a change from moist forest and grassland to today's hot desert; the main geological features date from the Pliocene to the Holocene (4 million to 10,000 years old).

Crocodiles live in this lake. Never swim or play at the water's edge.

It is very hot. Drink water and rest in the shade.

PlayOwl's advice: the lake has the world's largest Nile crocodile breeding ground, so stay well back from the water and never swim. Hippos live here too, so watch all wild animals from far away.

The heat can make people sick. The US National Weather Service says signs of heat exhaustion include heavy sweating, tiredness and dizziness; move to a cooler place, loosen clothing, use cool, wet cloths and take sips of water.

PlayOwl's advice, based on UNESCO's account of the island parks (the largest Nile crocodile breeding ground in the world, breeding hippos): no swimming or wading, and keep a wide distance from the shoreline and from wildlife.

NWS heat illness guidance: heat cramps may be the first sign; heat exhaustion brings heavy sweating, weakness, cool, pale, clammy skin and dizziness: move to a cooler place, loosen clothing, apply cool, wet cloths and offer sips of water; heat stroke is a medical emergency.