Based on Landsat images analysis from 2000 to 2019, a significant increase in thermokarst lake area was revealed in the Suola, Tanda and Taatta River basins, Central Yakutia. The lake area increased twice over the 20 years in the basins of the Suola and Taatta Rivers and by 25% in the Tanda River basin. It was found that the increase in the lake area occurs abruptly, determining the dynamics of the lakes development in the subsequent period, despite the presence of a general linear trend. The relationship between the changes in the state of the upper layer of permafrost and a sharp increase of thermokarst lake area was revealed. The main factor that leads to a change of the stable state of thermokarst forms are short-term (1-3 years) periods of abnormal temperature increase of the top ground layer. Such periods may be caused by a rare combination of hydrometeorological conditions, such as abnormally high snow water equivalent and annual precipitation and increased humidity of the seasonal thaw layer.