Eruption likely within days or weeks at Nevado del Huila volcano , agency warns . Colombian volcano 's eruption killed at least six people in November . Some 800 families under evacuation from high-risk area . Comment:
Eruption likely within days or weeks at Nevado del Huila volcano , agency warns . Colombian volcano 's eruption killed at least six people in November . Some 800 families under evacuation from high-risk area . Eruption would cause avalanche down Paez and Simbola rivers , officials say .