More than 20 years in the monitoring of the Earth's surface with spacecraft in the spring on a snow-covered ice of Lake Baikal regularly observe giant rings with diameter of up to 8 km. Most researchers agree that the appearance of rings connected with a different kind of activity of the lake bottom. This may be mud volcanoes, which are not uncommon in Baikal, or methane emissions of bottom sediments in the form of hot jets. Anyway, the determining factor for the appearance of rings are thermal processes. So as ice lies on the water, the thermal conductivity equations must also attract and equations of hydrodynamics. Thus, the study of rings on the lies lies solid basis of the mathematical description. The article gives some figures related to the rings. Briefly describes what led the joint consideration of the equations of fluid dynamics and heat transfer in the study of giant rings on a snow-covered Lake Baikal ice field.