The paper is concerned primarily with the analysis of pressure waves that can be generated by clouds of explosive gas mixtures in a free atmosphere which is initially at a uniform state. Since maximum effects are of prime interest, ignition and initial flame acceleration are considered to be out of scope, and the treatment is restricted only to the final stage of constant flame velocity when the flow field is self-similar. By the introduction of reduced blast-wave parameters as phase-plane coordinates, the problem is resolved into the determination of the appropriate integral curves on this plane. Salient properties of such solutions related to deflagrations are worked out in detail for the regimes of blast waves and acoustic fields. Results, including space profiles of gasdynamic parameters, have been computed for a specific case of a hydrocarbon-air mixture that is characterized by a specific heat ratio of 1.3, sound speed at N.T.P. of 345 m/sec, and volumetric expansion ratio corresponding to constant pressure deflagration of 7, covering a complete range of burning speeds from 0.5 m/sec to the Chapman-Jouguet deflagration of about 120 m/sec. Maximum overpressure ratios that can be generated by such flames in point-and line-symmetrical waves range from 0.53×10 −3, for the lower bound in the burning speed, up to 6 for the deflagration, while, for the average speeds of 5 to 10 m/sec, they are at a level of 0.05 to 0.10.