There are several ways to assess the ice strength before venturing onto the frozen surface of a lake to practice a sport, or recreation or scientific activity. In particular, the color, texture, and characteristics of the ice must be observed, as well as its thickness. It is also essential to check the water depth and the size of the body of water. One should also be mindful of the atmospheric temperature and weather conditions and keep in mind that ice takes time to form and melt. The ice cover of a frozen lake is never completely solid at the start and end of the winter season.