Possible physical mechanisms of the formation of the spin flame front in deflagrating gas mixtures are discussed. Conditions for the observation of a new physical phenomenon — the propagation of the spin flame front in a limiting propane—air mixture in an open narrow slot — are identified. Experimental techniques for investigating the spin mode of flame propagation in a gas mixture with low Reynolds numbers are suggested. The conditions where transport can affect the formation of a spin front in a gas—air mixture are formulated and prospects for future research are outlined.