[OE] Several AERIAL SHOTs of spring break-up on the Mackenzie River. TRAVELLING AERIAL SHOT of ice streaming down river. AERIAL SHOT of breaking ice floe. Other AERIAL SHOTs over Mackenzie River, including some shots from river bank. MS of ice floe moving slowly downstream, snow-capped mountain range in background. CS of uprooted tree stump on ice of river bank. TILT UP to MS of river, ZOOM OUT to MS of river. CS and ECU of ice melting in sunlight.