Pol Colonel Wuth Pathomreungkul of the 36th Ranger Regiment in Mae Sarieng district blamed one of the blazes on an inadequately extinguished cooking fire and the other on unattended candles or joss sticks.
The first fire at the Mae La Ma Luang camp in Sop Moei district destroyed the wood-frame, leaf-roofed shack of two women, ages 61 and 23.
The second, which occurred soon after, partially damaged a similar abode 500 metres away that was occupied by a 47-year-old man.
A March 21 fire at the same camp was believed caused by either a rekindled cooking fire or an electrical short-circuit.