**Paleoclimatologists have determined the suitable time for the settlement of America based on sea ice. Such conditions existed around 24,5-22 and 16,4-14,8 thousand years ago.** [Ice and ocean constraints on early human migrations into North America along the Pacific coast](https://www.pnas.org/doi/full/10.1073/pnas.2208738120) The first people to settle in America probably lived in parts of Beringia during the last Ice Age. Scientists don't know exactly when or how they traveled south, but it is believed that they went by the coast because a route through the interior was blocked by ice sheets. Using computer models and information about the North Pacific, researchers found times when it was possible for these early humans to travel along the coast. During the Ice Age, the water currents along the coast were stronger, making it harder to travel by boat. There were also big chunks of ice breaking off glaciers that would have made travel on land or sea more difficult. However, after these ice-breaking events, there were ice-free coastal areas and seasonal sea ice along the Alaskan coast until at least 15,000 years ago. This winter sea ice connecting islands and coastlines could have provided a food supply and a way for people to travel south either by boat or on foot. The researchers believe that early humans may have taken advantage of this sea ice. Based on evidence, they think that people were living south of the ice sheets by 16,000 years ago or even earlier. The researchers suggest that the most suitable times for coastal migration were 24.5 to 22,000 years ago and 16.4 to 14.8,000 years ago, when the climate conditions were good for year-round marine resources and different ways of traveling along the North Pacific coast.