A wind tunnel study of the effect of intermediate density ratio on saltation threshold

•The Titan Wind Tunnel (TWT) is used to collect new freestream threshold data.•We convert the data to dimensionless values as a function of density ratio, A(ρp/ρ).•This unique dataset confirms the slope of A(ρp/ρ) in the transitional region.•It also gives higher values of A(ρp/ρ) in this region outside of error bars.•The scatter in these transitional density ratio data invites continued investigation.