For the first two days of the fire, the high thermal energy made the plume highly buoyant; this, together with settled weather conditions, allowed the plume to rise to a great height with little cross-mixing. When the fire was reduced in intensity it was reported to be possible that the plume would be less buoyant and that ground-level smoke concentrations could then rise significantly. By 12 December, it was reported that the smoke cloud had reached northern France; it was expected to arrive in northern Spain by the weekend.